• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.772-776
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• 2006

A research about facial image recognition is studied in the most of images in a full race. A representative part, effecting a facial image recognition, is eyes and a mouth. So, facial image recognition researchers have studied under the central eyes, eyebrows, and mouths on the facial images. But most people in front of a camera in everyday life are difficult to recognize a fast change of pupils. And people wear glasses. So, in this paper, we try using Principal Component Analysis(PCA) for facial image recognition in blindfold case.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.149-154
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• 1997

We investigated the dominant eye of 123 Korean over twenty years old, then examined the refractive correlation of dominant eye, the unaided visual acuity and over-correlation. The results of these investigations are following. 91 persons of the whole number, 74%, have the dominant eye of right. The refractive correlation to the glasses are the high dominant eye. There are many men who are the same in unaided visual acuity. In men, they prefer to have the non-dominant eye but in women, they like better to have the dominant eye. The unaided visual acuity of ametropia, however, prefer to have the non-dominant eye in both men and women. In case of over-correction of an eye, there was affected the response of the other eye over 50% at the same time and the case of over-correction of dominant eye has more number than that of non-dominant eye.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1106-1111
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• 2006

To improve warpage, delamination and the chemical reaction between 2 different co-fired materials, the bonding behavior with common glass was studied. As shown in the previous paper, the phenomenon of the infiltration is different with the composition of the glass. In particular, in the case of low temperature melting glass, infiltration is experimented in this study. GA-1 glass is infiltrated among $BaTiO_3$ particles below $800^{\circ}C$ and is made by glass/ceramic composite. Until the laminate is fired under $850^{\circ}C$, provskite phase is observed. Although in the case of GA-12 glass, the temperature of the glass infiltration is lower than it of GA-l glass, the perovskite phase already disappears at $800^{\circ}C$. As a result, GA-1 and GA-12 glasses are infiltrated among particles at low temperature, however, the chemical reactivity of the glass/ceramic and sintering temperature should be considered.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.13-20
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• 1989

After sintering Si3N4 containing 20wt% of variable composition ratio of Y2O3 and Al2O3 at 1$600^{\circ}C$, the specimens were annealed at 125$0^{\circ}C$ and 135$0^{\circ}C$ for 5, 10, 15 hours in order to crystallize the remanining oxynitride glass phases. The main grain-boundary crystalline phases in the Si3N4-Y2O3-Al2O3 system were melilite and YAG. By annealing 15hrs. at 125$0^{\circ}C$, almost all of the glasses were crystallized. During the growth of melilite, lattice volyume of $\beta$-Si3N4 was increased as Al3+ and O2- ions in the oxynitride glass diffuse into $\beta$-Si3N4 lattice, but during the growth of YAG, lattice volume of $\beta$-Si3N4 was decreased by reverse diffusion of Al3+ and O2- ions. In case of crystallization of glass phase to melilite, thermal expansion of sample was decreased, but in case of crystallization to YAG, inverse phenomen on was observed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.227-234
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• 2006

Microstructures of free surface and interior of glass-ceramics obtained by heat treating silicate glass specimen containing electric arc furnace dust(EAF dust) were observed. The crystallization temperature, $T_c$ of glassy specimen was measured around $850^{\circ}C$ from the result of different thermal analysis so heat treatment temperature to obtain glass-ceramic specimen was selected as $950^{\circ}C$ for 1 hr. Glass specimens containing 50 wt% dust were amorphous, while glass specimens containing 70 wt% dust showed spinel crystal peaks in XRD results. In case of glass-ceramic specimens, spinel crystalline phase was appeared with willemite, and willemite crystal peak intensity increased with increasing dust contents. The fractured surface of glass specimens containing 50 wt% dust was smooth like mirror surface, but that containing 70 wt% dust showed spinel crystals of 10 ${\mu}m$ size in glass matrix. In case of glass-ceramic specimens, ZnO crystal particles of $2{\sim}5{\mu}m$ size were produced in free surface and glassy phase, spinel and willemite crystal phases existed in interior. There were no crystals in glasses containing 50 wt% dust, while glass containing 70 wt% dust had 14 vol% crystals. Crystallinity of glass-ceramic specimens containing 50 and 70 wt% dust were 19 and 43%, respectively. When microstructures of glass and glass-ceramic specimens were observed through SEM after TCLP experiment, glass specimens showed flaking phenomenon while glass-ceramic specimens showed a slight corrosion evidence without any cracks.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.33-41
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• 2003

There exists high hazard when transporting LPG as well as using, storing, and producing. For small scale LPG consumer, retailers deliver LPG to customers via a truck loading many LPG cylinders. Suppose there occurred a accident during LPG cylinder transfer, this could result in serious damages to the life and properties in the near or neighbor of the accident spot. In this regard, we made a quantitative risk analysis to estimate the possible damages and the probability through the identification of accidents causes and the simulation of the possible scenario. In this study, we made the Excel & Visual Basic computer program to perform quantitative LPG accident analysis. The simulation showed the following results. In case of UVCE(Unconfined Vapor Cloud Explosion), the effect within l0m of the accident spot showed very severe structural damages and even the accident can break the window glasses of the area of 150 m apart from accident spot. In case of TNT corresponding probit analysis, after 10 minutes LPG leaking, $75\%$ window glasses of 40 m distance was expected to be broken. And $16\%$ frames of 20m distance, $10\%$ frames of 40m distance was expected to be collapsed.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.66-75
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• 1992

The performance of heat transfer through double pane window has been investigated using experimental and numerical methods. The range of the gap distance between glasses are 0.5-10 cm. The convection heat transfer plays the dominant role for the case of the wide gap distance together with the large Rayleigh number and thereby, reduces the enhanced thermal resistance due to the increased air gap, while the conduction heat transfer does the major role for the case of small gap distance. In order to enhance the thermal insulation of the double pane window, the heat transfer of triple pane window, which is constructed to put one more glass at the middle of the double pane, is investigated to check the reduction of the convection heat transfer together with the effect of the radiation shield due to the presence of the additional glass. Further, a spacer is installed at the middle height of the double pane, and the effect of which on the suppression of the convective heat transfer is analyzed carefully, using experimental and numerical methods. For the case of the spacer-installation, the amount of energy saving is considered about 10%, but the energy saving increases a lot to 30-50% for the case of triple pane window, due to the substantial radiation shield effect of the presence of the additional glass.

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.147-158
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• 2017

Among the energy consumption in building, the heating energy takes the largest part. Therefore, it is important to minimize the heat energy loss in building for the reduction of overall energy use in construction. The most important points for the minimization of energy loss in building are insulation and airtightness. Especially, in wood houses, airtightness is very important for energy saving as well as increase of durability. However, the researches on airtightness of wood buildings have been started recently and are very deficient especially in Korea. In this study, air leakage properties and airtightness performance were evaluated for light-frame wood houses built in Daejeon and Chungnam area. Total 7 houses were evaluated, among which four houses (Case 1 to Case 4) were in the construction stage before interior finish and the other three houses (Case 5 to Case 7) were after completion of construction work. The tests for airtightness were conducted by pressurization-depressurization method, and the factors included in the measurements includes air leakage rate at 50 Pa (CMH50), air change rate at 50 Pa (ACH50), equivalent leakage area (EqLA) and EqLA per floor area. As a result of this study, key air leakage points in wood houses were found to be the gaps between floor and wall, the holes for wiring and plumbing, the double glasses windows and the entrance doors. The average value of ACH50 for the houses after completion of construction work was $3.5h^{-1}$ that was similar to Europe standard ($3.0h^{-1}$). ACH50 was proportional to EqLA per floor area but inversely proportional to the internal volume, the net floor area and the area of window.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.932-938
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• 2002

In structural applications, brittle materials such as soda-lime glasses and ceramics are usually subjected to multiaxial stress state. Brittle materials with cracks or damage by foreign object impacts are apt to fracture abruptly from cracks, because of their properities of very high strength and low fracture toughness. But in most cases, the residual strength of structural members with damage has been tested under uniaxial stress condition such as the 4-point bend test. Depending upon the crack pattern developed, the strength under multiaxial stress state might be different from the one under uniaxial. A comparative study was carried out to investigate the influence of stress state on the residual strength evaluation. In comparable tests, the residual strength under biaxial stress state by the ball-on-ring test was greater than that under the uniaxial one by the 4-point bend test, when a small size indendation crack was introduced. In the case that crack having an angle of 90deg. to the applied stress direction, the ratio of biaxial to uniaxial flexure strength was about 1.12. The residual strength was different from crack angles to loading direction when it was evaluated by the 4-point bend test. The ratio of residual strength of 45deg. crack to 90deg. one was about 1.20. In the case of specimen cracked by a spherical impact, it was shown that an overall decrease in flexure strength with increasing impact velocity, and the critical impact velocity for formation of a radial and/or cone crack was about 30m/s. In those cases that relatively large cracks were developed as compared with the case of indented cracks, the ratio of residual strength under biaxial stress state to one uniaxial became small.

• Journal of the Korean Ceramic Society
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• v.32 no.3
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• pp.385-393
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• 1995

Akali-resistant porous glass was prepared by phase separation in Na2O-B2O3-SiO2 system containing ZrO2 and MgO. ZrO2 was added for alkali-resistance and MgO for anti-cracking during leaching. Optimal content of ZrO2 for alkali-resistance was 7wt% and devitrification by heat treatment resulted from further addition. Pore size and pore volume were decreased and specific surface area was increased with ZrO2 addition due to depression in phase separation. Addition of 3mol% MgO to mother glass containing 7wt% ZrO2 was effective for anti-crack during leaching. In this case, with phase separation at 55$0^{\circ}C$ and 5$25^{\circ}C$ for 20 hrs. crack-free porous glasses could be prepared. The relation between pore size r and heat treatment time t at 55$0^{\circ}C$ was D=25.58＋18.16t. According to measurement of gas permeability, the mechanism of gas permeation was Knudsen flow. N2 and He permeability of porous glass which was prepared by heat treatment at 55$0^{\circ}C$ for 20 hrs. were 0.843$\times$10-7mol/$m^2$.s.Pa and 2.161$\times$10-7mol/$m^2$.s.Pa respectively.