• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.73-79
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• 2002

Fretting wear test in room temperature air was performed to evaluate the wear mechanism of fuel rod using a fretting wear tester, which has been developed for experimental study. The main focus was to compare the wear behaviors of fuel rod against support springs at different contact geometries (i.e. concave and convex) and slip directions (axial and transverse). The wear on the tube was examined by the surface roughness tester, which measures the volume. The result indicated that with change of contact geometry from 5N of normal load to 0.1mm gap, wear volume of tube Increased in the condition of concave spring, but slowly decreased in convex spring. From the results of SEM observation, wear mechanism of each test condition was also depend on the above contact parameters. The wear mechanism of each test condition in room temperature air is discussed.

• Transactions of Materials Processing
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• v.7 no.1
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• pp.81-93
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• 1998

Identification of forming limits of sheet metals is an important task to be done before the sheet metal forming processes. The information of the forming limit is indispensable for design of deformed shapes and related forming processes. This procedure becomes more important than ever as the auto-body becomes complicated and the number of auto-body parts is reduced for lower production cost. To identify the forming limit of sheet metals stretching with a hemispherical punch has gained popularity because of the convenient experimental procedure. The stretching experiment however has localized deformation or the shear band is originated from the non-unifrom deformation in the critical circum-stance instead of the absolute criterion. More accurate information of the forming limit therefore could be obtained by a more appropriate experiment to the real process. In this papaer an experiment program is devised to practivally identify the forming limits of sheet metals for auto-body parts. The experiment program contains not only stretching but deep-drawing Both forming experiments use the same hemispherical punch while they use different specimens. Deep-drawing experiments use speci-mens cut out in circular arc on both sides of circular blank to make it torn during the deep-drawing They also use speciments cut out straight in one side of a circular blank to make it deformed unevenly which causes local deformation during the deep-drawing. The experimental result demonstrates that the forming limit diagrams in the two cases show difference in their effective magnitude. The forming limit curve from deep-drawing is located lower than that from stretching. It is noted from the result that the deep-drawing process causes acceleration of localized deformation in comparison with the stretching process. From the experimental result the maximum value of forming limit could be pre-dicted for safe design.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.11-17
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• 2007

Turbulent in-situ mixing process is a new material process technology to get dispersed phase in nanometer size by controlling reaction of liquid/solid, liquid/gas, flow ana solidification speed simultaneously. In this study, mixing which is the key technology to this synthesis method was studied by computational fluid dynamics. For the simulation of mixing of liquid metal, static mixers investigated. Two inlets for different liquid metal meet ana merge like 'Y' shape tube having various shapes and radios of curve. The performance of mixer was evaluated with quantitative analysis with coefficient of variance of mass fraction. Also, detailed plots of intersection were presented to understand effect of mixer shape on mixing. The simulations show that the Reynolds number (Re) is the important factor to mixing and dispersion of $TiB_2$ particles. Mixer was designed according to the simulation, and $Cu-TiB_2$ nano composites were evaluated. $TiB_2$ nano particles were uniformly dispersed when Re was 1000, and cluster formation and reduction in volume fraction of $TiB_2$ were found at higher Re.

• Korean Journal of Materials Research
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• v.23 no.9
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• pp.537-542
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• 2013

Two types of Tb- and Na-substituted green phosphors $Ca_{(1-1.5x)}WO_4:Tb_x^{3+}$: and $Ca_{(1-2x)}WO_4:Tb_x^{3+},Na_x^+$ were synthesized with various x values, using a solid-state reaction. The former phosphors contained both substitutional and vacancy point defects, while the later had only substitutional defects. X-ray diffraction results showed that the main diffraction peak, (112), was centered at $2{\theta}=28.72^{\circ}$ and indicated that there was no basic structural deformation caused by substitutions or vacancies. The photoluminescence emission and photoluminescence excitation spectra revealed the optical properties of trivalent terbium ions, $Tb^{3+}$. Typical transitions, $^5D_3{\rightarrow}^7F_6,\;^7F_5,\;^7F_4$ and $^5D_4{\rightarrow}^7F_6,\;^7F_5,\;^7F_4,\;^7F_3$, and cross relaxations were observed. Subtle differences in the photoluminescence of green phosphors were observed as a result of the point defects. The FT-IR spectra indicated that some of the ungerade vibrational modes had shifted positions and changed shapes, spreading out over a wide range of frequencies. This change can be attributed to the different masses of $Tb^{3+}$ and $Na^+$ ions and $V_{Ca}$" vacancies compared to $Ca^{2+}$ ions. The gerade normal modes of the Raman spectra exhibited subtle differences resulting from point defects in $Ca_{(1-1.5x)}Tb_xWO_4$ and $Ca_{(1-2x)}Tb_xNa_xWO_4$.

• Journal of the Ergonomics Society of Korea
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• v.23 no.2
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• pp.1-12
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• 2004

The purposes of this study were to investigate the relationship between anthropometric data of foot and other body sizes. to categorize the foot shape of elementary school boys and to find out determinant factors related the foot that enable us to deduce the foot shape and size for the design of more comfortable shoes. Subjects of this study were 249 elementary school boys of age ranged from 6 to 11 residing Seoul and lncheon area. Anthropometric sizes were measured with the direct measurement method using Martin scales and the indirect measurement method using digital photos. Pearson's correlation, factor analysis. cluster analysis. analysis of variance, post-hoc test, and cross tabs were performed for statistical analysis of the data by SPSS program. From the investigation on the relationship between foot-related items and body items, most items of foot measure were significantly related to body size items. However, angle of the foot did not related to other body sizes although other height items and mass items of the foot did have relationships with other body sizes. Results of ANOVA indicated there were significant differences in foot-related items except for items of foot angle and all body anthropometric items by subjects' age. This implicates big toe angle, little toe angle and foot ratio factors are required in sizing shoes besides foot length. On the basis of cluster analysis using factor scores. three different foot shapes were categorized. Type 1 was large and wide foot, Type 2 was small and narrow foot with large toe angle. and Type 3 was medium foot with no deformity on big toe. These three groups show significant differences in almost all measurement items. However, Rorher index and foot angle didn't show any significant differences among groups. This implicates the foot shape can be a determinant of shoe size.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.245-255
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• 2001

Existing cut-and-cover tunnels are designed regardless of cut-slope under the assumption that the overburden weight of backfill soil acts on tunnel arch and the earth pressure at rest acts on tunnel walls. However, actual earth pressures acting on the tunnel lining depend on open-cut size composed of cut-slope and cut-width, and thus the tunnel lining shows a different structural behavior. This study investigated the effect of cut-slope on structural behavior of the cut-and-cover tunnel lining as follows; Firstly, a comprehensive numerical analysis method using FLAC2D code was used and verified by field measurements of tunnel profile. Secondly, based on the verified numerical analysis technique, earth pressure acting on the lining, and displacement and sectional force developed on the lining were estimated with various shapes of cut-slopes$30^{\circ}\;, 456{\circ},\; 60^{\circ},\; and\;75^{\circ}%). Numerical analysis results indicate that the steeper cut-slope shows the more displacement and moment of the tunnel lining.

• Journal of the Korea Fashion and Costume Design Association
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• v.13 no.4
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• pp.127-138
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• 2011

The style which is created by grafting the characteristics of goth onto haute couture designer works is called 'Haute goth'. The purpose of this study is to analyze the modem Goth fashion style based on Goth's historical background and characteristics. Also, I investigated the aesthetic characteristics of haute goth style appeared from the work of haute couture designers. Goth means a member of East Germanic people who invaded and settled in the Roman Empire from the 3rd to the 5th century. Goth style had been developed to the medieval European architecture style or the literature style of 18th~19th centuries and later it was reappeared in the gothic band in the late 20th century. Goth fashion shows the characteristics of the medieval times and Victorian times mixed with punk and fetish style. Goth fashion is expressed with the images of fear, darkness, mystique, dandy and eroticism. 'Dark esthetics' is realized through black clothes, pale complexion and silver accessories. Many designers like Alexander McQueen and John Galliano designed 'haute goth fashion' in various ways. The characteristics of 'haute goth' can be summarized in four things. It creates new images, seeks various changes and pursuits newness. It upgrades a street look style gothic fashion to a luxury high fashion and the creative design with artistic value. It also shows an experimental sprit by using a unique shapes, silhouettes, different materials and extreme images or creating new combination through the mismatch of opposite objects or emotions. Although it is rooted in the past because of the influences by late medieval times, Victorian times and Edwardian times, it displays enough of future-oriented historicism designs.

• Korean Institute of Interior Design Journal
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• no.12
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• pp.91-99
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• 1997

Alvar Aalto has pursued National Romanticism, cultural art movement in scandinavian peninsula, organic concepts of growth and suitability, comprehensive view of nature including a possibility of coexistance of human-being and the nature well harmonized. For instance, his design expressed local features of the nature, human emotions instead of geometical arts and mathematical principles. It is noteworthy today that he built up the identity with satrical architecture vocabularies, different from modern arch-itechtural idiology. The characte-ristics of his design related to interior architecture are collectively as follows; The first, Space discontinuity of the interior and exterior, gradual process by joints which are inclined to collage with many shapes in plan and section of the space and such joints are adjusted by sensual ways and stressed with inner collectivity in his works. The second, He pursued the architectural orderfor modern irreqularity, various changes and sensual harmonies. As result, free curved line, fan shape and irregular modeling were individually expressed by technics of natural features and national characteristics of Finland. The third, Organic synthesis. A harmony through med-ums in its space, materials and space effectiveness relations are made and expressed for mixed design especially harmonized of all the materials he planned, entire harmony with total design, itemized details, materials and furnitures in entire space. The fourth, The interest of the nature based on his sense harmonized with nature made him mainly use native materials, lumbers and red bricks masonry and showed and arranged various interior sky light and grazed in to let natural light in, harmony with garden to sensually cohere to the nature and courtyard, etcetera. His major subject are to direct architectural developments through the nature and human-being in his works. At this point, it is considered that his direction of the locality and independence as a human-being made the concepts of organic space structure possible.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.929-933
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• 2014

The measurement of joint angle is important to evaluate the patient's disability. The modified fiber tip and light propagation of the developed fiber sensor were investigated to increase the range of angle detection. Different shapes of fiber tips were manufactured with a polishing machine to deliver light signal in various patterns. Output signals were analyzed to obtain joint angle change with inverse polynomial models. The measured joint angles were displayed with LabVIEW program and the reliability was tested by comparing with a commercial angle sensor. This method can be used in rehabilitation field to determine patient's progress.

• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.731-740
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• 2003

Since motion estimation remove the redundant data to employ the temporal correlations between adjacent frames in a video sequence, it plays an important role in digital video coding. And in the block matching algorithm, search patterns of different shapes or sizes and the distribution of motion vectors have a large impact on both the searching speed and the image quality. In this paper, we propose a new fast block matching algorithm using the small-cross search pattern and the block-based gradient descent search pattern. Our algorithm first finds the motion vectors that are close to the center of search window using the small-cross search pattern, and then quickly finds the other motion vectors that are not close to the center of search window using the block-based gradient descent search pattern. Through experiments, compared with the block-based gradient descent search algorithm(BBGDS), the proposed search algorithm improves as high as 26-40% in terms of average number of search point per motion vector estimation.