• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.293-299
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• 2001

The aim of this study was to evaluate the effect of the distance of the light tip to the surface of restoration and exposure time on the polymerization of surface and 2mm below the surface of light-activated composite resins. Two light-activated composite resins were used. From the experiment, the following results were obtained. 1. Relative light intensity rapidly decreased when distance of the light tip to the surface of material is more than 2mm(p<0.05). 2. In all groups, microhardness was increased according to the increase of relative light intensity and exposure time(p<0.05). 3. The distance of the light tip to the surface of restoration and exposure time more affected 2mm below the surface rather than the surface(p<0.05). 4. Although exposure time was increased, difference of microhardness of the 2mm below the surface with the distance of the light tip to the surface of restoration was relatively high in Z100 between below 4mm and other groups and Z250 between below 2mm and other groups(p<0.05).

• Journal of Korea Multimedia Society
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• v.11 no.11
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• pp.1501-1514
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• 2008

The face shape extracted by the depth values has different appearance as the most important facial information. The face images decomposed into frequency subband are signified personal features in detail. In this paper, we develop a method for recognizing the range face images by multiple frequency domains for each depth image using the modified fuzzy c-mean algorithm. For the proposed approach, the first step tries to find the nose tip that has a protrusion shape on the face from the extracted face area. And the second step takes into consideration of the orientated frontal posture to normalize. Multiple contour line areas which have a different shape for each person are extracted by the depth threshold values from the reference point, nose tip. And then, the frequency component extracted from the wavelet subband can be adopted as feature information for the authentication problems. The third step of approach concerns the application of eigenface to reduce the dimension. And the linear discriminant analysis (LDA) method to improve the classification ability between the similar features is adapted. In the last step, the individual classifiers using the modified fuzzy c-mean method based on the K-NN to initialize the membership degree is explained for extracted coefficient at each resolution level. In the experimental results, using the depth threshold value 60 (DT60) showed the highest recognition rate among the extracted regions, and the proposed classification method achieved 98.3% recognition rate, incase of fuzzy cluster.

• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.897-905
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• 2014

The foliage of sweet potato [Impomoea batatas (L.) Lam] is an excellent source of food material due to the functional components of polyphenol and carotenoid. In this study, the lightness (L-value), polyphenol contents, and DPPH radical scavenging activity of the foliage of Shinwhangmi, Hayanmi and Suioh cultivars harvested after different cultivation periods (60, 90 and 120 days after planting) and according to tip locations (1st~5th, 6th~10th, 11th~15th tips) were investigated. As a result, Shinwhangmi showed a lower lightness value (60 days after planting and 1st~5th tips). The longer the cultivation periods and the closer the tips, the higher the contents of polyphenol and DPPH radical scavenging activity were in lyophilized foliage of Shinwhangmi, Hayanmi and Suioh. In the 1st~10th tip of Shinwhangmi, Hayanmi and Suioh cultivated for 90 days and dried by 2 step hot-air (1st: $70^{\circ}C$ for 8 hr, 2nd: $80^{\circ}C$ for 4 hr), the polyphenol and ${\beta}$-carotenoid contents were 5.0, 3.9 and 4.0 mg/g and 75.6, 71.6 and 63.1 mg/g, respectively. The DPPH radical scavenging activities and ABTS radical scavenging activities ($EC_{50}$) were 0.29, 0.36 and 0.33 mg and 0.12, 0.15 and 0.11 mg, respectively. These antioxidative activities were over two times stronger than spinach.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.221-225
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• 1994

This experiment was conducted to identify the optimal in vitro propagation condition of Cnidii rhizoma (Cnidium officinale Makino). It was effective to reduce contamination and improve regeneration of shoot when shoot tips taken in July were cultured in 1/2 strength Murashige and Skoog medium supplemented with 500 mg/L carbenicillin disodium 1.0 mg/L BA and 1.0mg/L $GA_3$followed by surface sterilization of explant source in solution of 1% sodium hypochlorite for 20 minutes. When shoot tips were 쳐cultured in 1/2 strength MS medium with 0.5 mg/L BA and 60 g/L sucrose, shoot elogation and subsequent multiplication of the formed shoot were favorable than in other media. Regenerants were well rooted in 1/2 strength MS medium containing 3.0 mg/L NAA.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.60-65
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• 2004

Kim et al. described and compared other methods of measuring stress triaxiality using the displacements near the side necking, proved the validities of these models and explored the effect of location where the displacements are measured using three-dimensional finite element analysis for a standard CT specimen with 20% side-grooves. In this paper, the applicability of these models to various specimen and materials are examined in detail. To consider the effects of side groove, thickness of specimen, crack length, specimen geometry and strain hardening exponents, three-dimensional finite element simulation has been performed for various specimen geometries. For a case without a side groove, in the whole the difference between the stress triaxilaity analytically evaluated and directly determined is similar. For a case with a 20% side groove the stress triaxiality is measured at the area where ${\theta}$ is smaller than $60^{\circ}$, which excludes a side grooved area.

• Journal of Fashion Business
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• v.11 no.3
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• pp.1-14
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• 2007

This research to reveal the foot types of old males consisted of two parts. First, a questionnaire was given for 180 old men in their 60s and above who live in Busan. Second, based on this survey on the reality of shoes wearing, direct and indirect measurement were held for 200 old gentlemen. The findings are as follows: 1. Survey Results of Shoes Wearing Reality In the investigation into the reality of shoes possession and wearing, most of old males favored active casual shoes with comfortable materials (40.8%). Hardened skin (23.6%) was the greatest in foot deformation and side effects resulting from shoes wearing, while the big toe (20.1%) was most uncomfortable. The greatest requirement for comfortable shoes was shoes making feet comfortable with a good sense of wear (41.0%), followed by shoes with the soft sole to absorb shock (31.7%), shoes with diverse sizes according to shoes width (13.7%), and shoes made of soft materials in consideration of various foot shapes. 2. Results of Foot Measurement Experiments Busan's males in their 60s and above were 166.31cm (Height), 63.51kg (weight), 23.94cm (foot length), 9.75cm (foot width), and 24.26cm (instep girth). The big toe angle of old males was $11.22^{\circ}$ and the little toe angle $14.70^{\circ}$. Four foot types were classified: 1 (long big foot), 2 (small inside-developed foot), 3 (toe-tip-gathered foot), and 4 (thin flat foot).

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.219-226
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• 2003

The fatigue crack growth behavior of the SA516/60 steel used for pressure vessels was examined experimentally at room temperatures $25^{\circ}C$,$-30^{\circ}C$, $-60^{\circ}C$, $-80^{\circ}C$, $-100^{\circ}C$ and $-120^{\circ}C$ with stress ratio of R=0.05, 0.1 and 0.3. fatigue crack propagation rate da/dN related with stress intensity factor range $\Delta$K was influenced by stress ratio in stable than fatigue crack growth (Region II) with an increase in $\Delta$K. The resistance of fatigue crack growth at low temperature is higher compared with that at room temperature, which is attributed to the extent of plasticity-induced by compressive residual stress according to the cyclic loads. Fractographic examinations reveal that the differences of the fatigue crack growth characteristics between room and low temperatures are explained mainly by the crack closure and the strengthening due to the plasticity near the crack tip and roughness of the crack faces induced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2097-2102
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• 2011

Discharge analysis technique for dielectric liquid was presented by using the Finite Element Analysis (FEA) under a lightning impulse incorporating two-phase flow phenomena which described gas and liquid phases in discharge space. Until now, the response of step voltage has been extensively explored, but that of lightning impulse voltage was rarely viewed in the literature. We, therefore, developed an analyzing technique for dielectric liquid in a tip-sphere electrode stressed by a high electric field. To capture the bubble phase, the Heaviside function was introduced mathematically and the material functions for the ionization, dissociation, recombination, and attachment were defined in liquid and bubble, respectively. By using this numerical setup, the molecular dissociation and ionization mechanisms were tested under low and high electric fields resulted from the lightning impulse voltage of 1.2/50 ${\mu}s$. To verify our numerical results, the velocity of electric field wave was measured and compared to the previous experimental results which can be viewed in many papers. Those results had good agreement with each other.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.70-77
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• 2019

This study presents the numerical investigation of the trajectory of rocket launched from a helicopter. The nonlinear mathematical model of armed configuration of UH-60 helicopter was developed while Hydra 70 unguided rocket was modeled to simulate the rocket behavior. The effects of various inflow models on the launched rocket trajectory are obtained. Similarly, rocket launch simulation was performed to determine the unsafe flight maneuver condition where the rocket trajectory is critically close to the helicopter main rotor tip path plane.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.519-529
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• 2010

In the present study, unsteady calculations have been performed to simulate flows around a UH-60A full configuration including main rotor, fuselage, and tail rotor. A flow solver developed for helicopter aerodynamic analysis was used for the simulation of the complete helicopter in high-speed and low-speed forward flight. Unsteady vibratory loads on the main rotor blades were compared with flight test and other calculated data for the assessment of the present flow solver. Aerodynamic interaction of the three components of the helicopter was investigated by comparing with the results of main-rotor-alone, main rotor and fuselage, and tail-rotor-alone configurations. It was found that the existence of the fuselage has an effect on the normal force distribution of the main rotor by varying downwash distribution on the rotor disc, and tip vortices trailed from the main rotor strongly interact with the tail-rotor.