• Information Systems Review
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• v.8 no.1
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• pp.1-24
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• 2006

Now, the Korean footwear industry needs the concrete enhancement of its competitive edge for regaining of its previous well known reputation. For this purpose, this study emphasizes the cooperation between the members through the supply chain of Korean footwear industry, as a c-SCM(Collaborative Supply Chain Management) by aid of information system. The key issue will be how well to coordinate operations flow not only through internal process stages, but also through entire external supply chain stages. In other words, the target goal must be the system optimization through the entire supply chain beyond the local optimization of internal supply chain process. We, at first, analyze the traditional structure of supply chain in Korean footwear industry and find out critical problems, and then, we develop the collaborative information framework in conjunction with several collaborative process modules. The suggested collaborative production & supply planning system was designed for sharing information and it is based on ebXML(electronic business eXtensible Markup Language) framework. In this way, the enhancement of the efficiency and competitiveness can be expected through the synergy effect of coordination of information and material flow, the reduction of lead times, and production costs.

• Korean Journal of Plant Tissue Culture
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• v.22 no.5
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• pp.299-306
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• 1995

The objective of this study is to establish an efficient celll culture system for somatic embryogenesis in Ostericum koreanum and Angelica purpuraefolia. The highest frequency of embryogenic callus on immature seeds of O. konanum and A, purpuraefolia. was obtained when seeds were cultured on MS medium containing 0.1 mg/L 2,4-D and 0.1 mg/L BA. However somatic embryos were formed directly from the edge of cotyledon and hypocotyl of plant which regenerated on medium supplemented with 0.1-3.0 mg/L NAA. Immature seed explane cultured at 25$\pm$2$^{\circ}C$ after 10 days treatment at 5$^{\circ}C$ produced embryogenic callus and somatic embryos, and these differentiated into whole plane. Addition of glutamine and coconut milk to media did not enhance the frequency of somatic embryogenesis in immature seed cultures of A. purpuraefolia. However in immature seed culture of O. koreanum, the frequency of somatic embryogenesis were increased on media supplemented with glutamine and 10% coconut milk. Especially addition of glutamine to the medium substituted effect of NH$_4$N0$_3$ in constast to coconut milk. The highest frequency of conversion somatic embryos into plantlet was 89.1% on MS basal medium Embryogenic calli were grown vigorously when maintained on medium with 0.01 mg/L 2,4-D and 0.01 mg/L BA.

• Composites Research
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• v.18 no.6
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• pp.9-18
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• 2005

With the wide applications of fiber-reinforced composite material in aero-structures and mechanical parts, the design of composite joints have become a very important research area because the joints are often the weakest areas in composite structures. This paper presents an analytical study of the stress distributions in mechanically single-fastened and multi-fastened composite laminates. The finite element models which treat the pin and hole contact problem using a contact stress analysis are described. A dimensionless stress concentration factor is used to compare the stress distributions in composite laminates quantitatively In the case of single-pin loaded composite laminate, the effects of stacking sequence, the ratio of a hole diameter and the width of a laminate (W/D ratio), the ratio of hole diameter and distance from edge to hole (E/D ratio), friction coefficient and clamping force are considered. In the case of multi-pin loaded composite laminate, the influence of the number of pins, pitch distance, number of rows, row spacing and hole pattern are considered. The results show that P/D ratio and E/D ratio affect more on stress distributions near the hole boundary than the other factors. In the case of multi-pin loaded composite laminate, the stress concentration in the double column case is better than the other cases of multi-pin loaded composite laminate.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.67-75
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• 1999

The use of composite restorative materials is established due to continuing improvements in the materials and restorative techniques. Composite resins are widely used for the restoration of cervical lesions because of esthetics, good physical properties and working time. There are several types of cavity design for class V composite resin filling, but inappropriate cavity form may affect bonding failure, microleakage and fracture during mastication. Cavity preparations for composite materials should be as conservative as possible. The extent of the preparation is usually determined by the size, shape, and location of the defect. The design of the cavity preparation to receive a composite restoration may vary depending on several factors. In this study, 5 types of class V cavity were prepared on each maxillary central incisor. The types are; 1) V-shape, 2) round(U) shape, 3) box form, 4) box form with incisal bevel and 5) box form with incisal bevel and grooves for axial line angles. After restoration, in order to observe the concentration of stress at bonding surfaces of teeth and restorations, developing a 2-dimensional finite element model of labiopalatal section in tooth, surrounding bone, periodontal ligament and gingiva, based on the measurements by Wheeler, loading force from direction of 45 degrees from lingual side near the incisal edge was applied. This study analysed Von Mises stress with SuperSap finite element analysis program(Algor Interactive System, Inc.). The results were as follows : 1. Stress concentration was prevalent at tooth-resin bonding surface of cervical side on each model. 2. In model 2 without line angle, stress was distributed evenly. 3. Preparing bevel eliminated stress concentration much or less at line angle. 4. Model with round-shape distributed stress concentration more evenly than box-type model with sharp line angle, therefore decreased possibility of fracture. 5. Adding grooves to line angles had no effect of decreasing stress concentration to the area.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.30-39
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• 2010

This study evaluated the influence of the type of restoration and the amount of interdental spacing on the stress distribution in maxillary central incisors restored by means of porcelain laminate veneers and direct composite resin restorations. Three-dimensional finite element models were fabricated to represent different types of restorations. Four clinical situations were considered. Type I, closing diastema using composite resin. Labial border of composite resin was extended just enough to cover the interdental space; Type II, closing diastema using composite resin without reduction of labial surface. Labial border of composite resin was extended distally to cover the half of the total labial surface; Type III, closing diastema using composite resin with reduction of labial surface. Labial border of the preparation and restored composite resin was extended distally two-thirds of the total labial surface; Type IV, closing diastema using porcelain laminate veneer with a feathered-edge preparation technique. Four different interdental spaces (1.0, 2.0. 3.0, 4.0 mm) were applied for each type of restorations. For all types of restoration, adding the width of free extension of the porcelain laminate veneer and composite resin increased the stress occurred at the bonding layer. The maximum stress values observed at the bonding layer of Type IV were higher than that of Type I, II and III. However, the increasing rate of maximum stress value of Type IV was lower than that of Type I, II and III.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.2
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• pp.86-94
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• 2002

This study was carried out to identify the relationship between naturally introduced vegetation on the abandoned coal mine lands and the surrounding forest, and to select the indigenous tree species for the revegetation of the real mine lands in Taeback, Kangwon Province, Korea. The apparent species in the surrounding forest of Sododong were 9 species of tree layer, 13 species of subtree layer, 23 species of shrub layer and 23 species of herb layer, respectively. The dominant species in Sarijae were 6 species of tree layer, 15 species of subtree layer, 31 species of shrub layer and 25 species of herb layer, respectively. The plant species in the abandoned real mine land were 31 species in Sododong and 30 species in Sarijae, respectively. The number of plant species in the abandoned coal mine land was smaller than the surrounding forest. The common species of the coal mine lands and the surrounding forest were 6 species(Betula schimidtii etc.) in Sododong and 4 species(B. costata etc.) in Sarijae. It was considered that the species in the coal mine lands introduced from the species of top layer in the surrounding forest. Especially, B. costata in Sarijae showed the edge effect which regenerates the vegetative community from the boundary area of coal mine land and surrounding forest. Natural revegetation in Sododong was also progressing by the invasion of tree species in surrounding forest, such as B. schmidtii. Consequently, natural revegetation in the disturbed coal mine lands may be related to the species composition of the surrounding forest.

• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.728-734
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• 2004

The effect of microstructure of WC-Co substrates which have different WC grain sizes from submicron to 5 $\mu$m on the diamond-substrate adhesion strength was investigated. The substrates were pre-treated by two methods : chemical etching with Murakami's solution and subsequently with $H_2SO_4$, and thermal heat-treatment. The adhesion strength was estimated by degree of peeling after Rockwell indentation. Diamond films of 20 $\mu$m thickness deposited on the heat-treated substrates showed an excellent adhesion strength at the load of 100 kg, which ascribed to the large and elongated WC grains. However, the cutting edge of insert was deformed after heat treatment and the surface morphology of heat treated substrate strongly affected on the surface roughness of the deposited diamond films. On the contrary, the diamond film of 10 $\mu$m in thickness on the chemically etched substrates of average WC grain size over 2 $\mu$m showed good adhesion strength enough not to peel-off under a load of 60 kg. Especially, the substrate of average WC grain size over 5 $\mu$m exhibited much improved reliability of adhesion comparing with the substrate of average grain size under 2 $\mu$m. No substrate deformation was observed in this case after the chemical etching, which is more advantageous and more practical in terms of precious machining than the heat treatment case.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.794-801
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• 2017

When a radial wheel is placed so as to partially overlap a conductive plate and rotated, a lift force is generated on the wheel, a thrust force along the edge, and a lateral force which tends to reduce the overlap region. When several of these wheels are combined, it is possible to realize a system in which the stability of the remaining axes is ensured, except in the traveling direction. To validate the overall characteristics of the multi-wheel system, we propose a transfer system levitated magnetically using radial electrodynamic wheels. The proposed system is floated and propelled by four wheels and arranged in a structure that allows the thrusts generated by the front and rear wheels to offset each other. The dynamic stability of the wheel and the effect of the pole number on the three-axial forces are analyzed by the finite element method. At this time, the thrust and levitation force are strongly coupled, and the only factor affecting them is the wheel rotation speed. Therefore, in order to control these two forces independently, we make use of the fact that the ratio of the thrust to the levitation force is proportional to the velocity and is independent of the size of the gap. The in-plane and out-of-plane motion control of the system is achieved by this control method and compared with the simulation results. The experimental results show that the coupled degrees of freedom can be effectively controlled by the wheel speed alone.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.2
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• pp.147-153
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• 2001

Objective: The present study was performed to investigate the efficiency of partial laser assisted hatching (p-LAH; lased 1/2 ZP width from ZP edge) on hatching of mouse blastocysts. Methods: We used non-contact $1.48{\mu}m$ diode laser (MTM, Switzland) to create a precise hole on zona pellucida. 2-cell embryos were collected from the mouse (ICR) oviduct at 48 hours after hCG administration. Collected 2-cell embryos were cultured in the P-1 medium supplemented with 0.4% BSA. For experiments, embryos at 8-cell stage were used after $20{\sim}22$ hours in culture. After conventional (c-LAH) or partial laser assisted hatching, the embryos were further cultured in P-1 medium supplemented with 0.4% BSA for 3 days. To compare efficiency of complete and partial laser assisted hatching, hatching rate, hatching time and blastocyst diameter and zona pellucida thickness at hatching time were investigated. Embryos were examined every 12 hours. Blastocyst diameter and zona pellucida thickness at hatching time were measured with an ocular micrometer. Results: Hatching rates of p-LAH group (84.2%) was significantly higher than that of control group (39.3%), but there was no difference between the p-LAH (84.2%) and c-LAH (91.2%). p-LAH group was hatched 12 hours earlier than control group, but hatched 12 hours later than c-LAH group. The diameter of blastocyst at hatching time of p-LAH group ($113.1{\pm}6.4{\mu}m$) was smaller than that of control group ($122.2{\pm}5.0{\mu}m$), but larger than that of c-LAH group ($102.2{\pm}2.7{\mu}m$). Zona pellucida thickness at hatching time of p-LAH group ($6.4{\pm}0.9{\mu}m$) was thicker than that of control group ($4.5{\pm}1.5{\mu}m$), but thinner than that of c-LAH group ($10.0{\pm}0.8{\mu}m$). Conclusion: These results suggest that p-LAH may maintains the cell arrangement of early embryos to ensure successful development and prevent precocious hatching of blastocyst when compare to c-LAH and conventional (acidic tyrode) AH. Thus, p-LAH may provide a valuable and effective AH technique for human ART program.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.173-180
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• 2000

To determine the effect of base curve and diameter of soft contact lenses on the fitting under the various corneal curvature, the model eyes which was made of either stainless steel or ordinary wood, were used as the substitutes for human eyes. The evaluations of fit of the soft contact lenses on both wood model eyes and human eyes were found to be very similar to each other. All the contact lenses except very thin ones became flat after fit on the stainless steel model eyes because the model eye could not preserve enough moisture to hold the edge of contact lenses on the steel ball's surface. The relationships between the base curves of contact lenses and radii of cornea for the optimum (normal) fit were measured as follows : corneal curvature (C.C)<7.6 mm : base curve(B.C) 8.4 mm, C.C 7.6~7.8 mm : B.C 8.4~8.5 mm. C.C 7.8~8.1 mm : B.C 8.6 mm. It is concluded that larger base curve is required for the eyes which have abnormal bulge on its cornea. It is found that very thin soft contact lenses can be easily twisted or folded regardless of moisture content when they were fit on the relatively dry eyes(corneas).