• 한국가시화정보학회:학술대회논문집
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• 2004.12a
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• pp.1-13
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• 2004

A scanning stereo-PIV system was developed to measure the three-dimensional distribution of three-component velocity in a turbulent round jet. A laser light beam produced by a high repetition rate YLF pulse laser was expanded vertically by a cylindrical lens to form a laser light sheet. The light sheet is scanned in a direction normal to the sheet by a flat mirror mounted on an optical scanner, which is controlled by a programmable scanner controller. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and stereoscopic PIV method was adopted to acquire the 3D-3C-velocity distribution of turbulent round jet in an octagonal tank filled with water. The jet Reynolds number was set at Re=1000 and the streamwise location of the measurement was fixed at approximately x = 40D. Time evolution of three-dimensional vortical structure, which is identified by vorticity, is visualized. It revealed that the existence of a group of hairpin-like vortex structures was quite evident around the rim of the shear layer of the jet. Turbulence statistics shows good agreement with the previous data, and divergence of a filtered (unfiltered) velocity vector field was $7\%\;(22\%)$ of root-me an-squared vorticity value.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.312-315
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• 2002

This paper summarizes the results of a numerical study conducted to analyze the effect of selected process parameters on material flow and thread profile in thread rolling of large diameter blanks. Based on the previous work where a plane strain mode was found to provide a reasonable approximation of the thread rolling process, the effect of varying thread form, friction factor, flow stress, and blank diameter on effective strain and thread height was analyzed using the finite element code DEFORM. This study show that effective strain for flank angle, that blank diameter had important effect on the as-rolled thread while flow stress, friction factor, and crest round of dies had significant impact on effective strain at the thread root and crest and load of thread rolling. While the rate of strain harding was found to have an effect on the crest profile, the results indicate that it is the primary factor responsible for seam formation in rolled threads.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.1 s.33
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• pp.55-67
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• 1990

This is a review on the longitudinal transformation of the Japanese trousers, which is prepared as a pre-study for the comparative analysis of the forms of Korean and Japanese folk trousers. The special traits of the Japanese trousers are found to be as follows: 1) The Japanese trousers seem to have their root in the Northern-Asian or Schithian culture. 2) While the ancient forms of Japanese trousers, esp., those of the 8C before include the same types as Korean folk trousers, the Medieval and Recent era trousers quite differ and transform themselves into the unique Japanese type. 3) All Japanese trousers can largely be classified into formal and functional trousers. Formal trousers play important role as one of the ceremonial wardrobe and are treated rather as an outermost-wear than as an inner-wear. 4) The formal trousers have skirt-like features with much fullness as are presented in many deep pleats, long crotch lines and long sashes connected to the belt; the femine trousers even omit crotch line. 5) The principal forms of Japanese trousers consist of I, $\wedge,\;\wedge$; the $\lambda$ form of Korean and Chinese type had never existed. 6) Varieties of the composite type of Japanese-Western style appear among the trousers of recent time.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1100-1106
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• 2009

This study intends to develop a pulse discharge device to strengthen the pushing power by expanding the cavity of the anchor settlement to form a spheric root for the purpose of constructing the economical and stable anchor. and, a series of field test were carried out in order to check applicability of machines of pulse powered underreamed anchors. Through the experiments, the electrical characteristics of the pulse power equipment had been identified it and the dynamic pressure generated from the subsequent change had been measured. Here, the measured dynamic pressure is the cavity expansion pressure to impact on the ground around the anchor settlement. Since this pressure has effects of cavity expansion and bored surface hardening with dynamic hardening effects on the anchor settlement, it is expected that it will largely contribute the increase of pushing power with a strong frictional resistance.

• Korean Institute of Interior Design Journal
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• v.18 no.3
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• pp.66-73
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• 2009

In the digital age, as it is ambiguous to distinguish between the original and a replica, the order of reproduction which is more realistic than the reality is becoming a new cultural order. Before the period when digital paradigm dominates, always the reality has been an object to be copied. But, today is an age of Simulacre where code of digital technology dominates. Such a phenomenon is shown in the construction space without exception Gilles Deleuze who was a representative philosopher of the post-structuralism depicted the concept of Simulacre as an instant 'event' passing by without change in an object or substance. As the result of analyzing what kinds of feature for the concept of event is expressed in the digital space, a diagram itself could be a design process, the digital space with correlation was able to be created through the change in the meaning according to the changing image and my body which was the leading part to form primary space. In such a meaning, this study pays attention to Deleuze's 'Event(Simulacre)' concept. At this transitional period when a new concept of digital space is about to take root, the modern philosophers' theories and the discussions about spatial relativity should be continually studied, along with the development of spacial theories for the modem construction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1275-1289
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• 1996

The plane elasticity problem of collinear cracks in a layered medium is investigated. The medium is modeled as bonded structure constituted from a surface layer and a semi-infinite substrate. Along the bond line between the two dissimilar homegeneous constituents, it is assumed that as interfacial zone having the functionally graded, nonhomogeneous elastic modulus exists. The layered medium contains three collinear cracks, one in each constituent material oriented perpendicular to the nominal interfaces. The stiffness matrix formulation is utilized and a set of homogeneous conditions relevant to the given problem is readily satisfied. The proposed mixed boundary value problem is then represented in the form of a system of integral equations with Cauchy-type singular kernels. The stress intensity factors are defined from the crack-tip stress fields possessing the standard square-root singular behavior. The resulting values of stress intensity factors mainly address the interactions among the cracks for various crack sizes and material combinations.

• Journal of Plant Biology
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• v.37 no.1
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• pp.53-67
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• 1994

The opal phytolith types in Oryza sativa L. were examined with light and scanning electron microscope, and we suggested the standard tenninoligies based on original cells of the phytoliths in situ. The distinctive fonus of opal phytoliths were observed in all plant parts such as leaf blade, leaf sheath, culm, root, glume, lemma, and palea. The phytolith fonus originated from long cell, short cell, and dennal appendages were different from part to part. The opal phytoliths derived from the long cells showed the most various form: twelve types were identified based on side wall shape. The results showed that the leaf blade did include almost all types of opal phytolith observed in the other parts of rice.f rice.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.551-556
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• 2008

Purpose: Cemental tear is an uncommon form of root fracture that can lead to rapid localized attachment loss. When it is exposed in the periodontal pocket, it should be removed to prevent accumulation of dental plaque and calculus. Material and Methods: 2 patients were diagnosed as a cemental tear and they were treated with conventional flap operation and subgingival curettage. Additional treatments such as bone graft or guided tissue regeneration were not performed. Result: Symptoms subsided after the treatment. Periodontal pocket has been reduced but no gain of clinical attachment was observed. Remnant of cemental fragment remained after curettage. However, periodontal pocket was stably maintained and there was no recurrence. Conclusion: Periodontal attachment loss associated with cemental tear can be successfully treated with conventional periodontal surgical and nonsurgical procedures.

• International Journal of Railway
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• v.9 no.1
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• pp.1-9
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• 2016

In order to achieve a comprehensive utilization of railway networks, it is necessary to accurately assess the timetable indicators that effect the train operation. This paper describes the parameter calibration for two timetable indicators: scheduled running time and scheduled dwell time. For the scheduled running time, an existing model is employed and the single timetable parameter (percentage of minimum running time) in that model is optimized. For the scheduled dwell time, two intrinsic characteristics: the significance of stations and the average headway at each station are proposed firstly to form a new model, and the corresponding timetable parameters (the weight of the significance and the weight of the average headway) are calibrated subsequently. The Floyd Algorithm is used to obtain the connectivity among stations, which represents the significance of the stations. A case study is conducted in a light rail transportation system with 17 underground stations. The results of this research show that the optimal value of the scheduled running time parameter can be automatically determined, and the proposed model for the scheduled dwell time works well with a high coefficient of determination and low relative root mean square error through the leave-one-out validation.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.30-39
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• 1998

Carrot seedling emgryos showing variations in cotyledon number were selected and anatomical comparisons of the embryo vascular systems were performed between the variants and normal two cotyledonary (5) embryos from 800 seedings germinated . Externally, all of the four and six cotyledonary embryos had two cotyledonary petioles. Each of the cotyledonary petioles divided into two or three on the upper part fo the petiole which result in four and six cotyledons, respectively. However, the embryos had three different cotyledonary petioles in the three cotyledonary embryos. On the basis of the pattern of vascular system, the four and six cotyledonary embryos had the same basic vascular system as fnormal two cotyledonary embryos, Therefore the cotyledon number abnormality could result from the branching split of the abnormally thickened upper part of the cotyledonary petiole. However, the three cotyledonaryembryos had a different vascular system from the normla two cotyledonary embryos. They could be regarded as different varieties form the two cotyledon embryos. All embryos observed had short cylindrical plumule sheath which formed by the fusion of the cotyledon bases. The presence of plumule sheath strontgly implied that the initiation of the cotyledons was not from the two localized primordia but from the circular proimordiu formed at the blobular stageof embryo, and it is not consistent with current views of cotyledon initiation. On the formation of the primary vascular system of carrot seedlings, it is suggested that the primary vascular system of the plumule was formed independently from that of the root-hypocotyle-cotyledon system.