• Journal of Korean Institute of Industrial Engineers
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• v.33 no.2
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• pp.273-281
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• 2007

The decision of how long performing system burn-in must be answered with a probabilistic model of a system lifetime at which infant mortality failures created during assembly processes are quantified. In this paper, we propose such a model which is modified from previous results. Using the system model, we derived system reliability in terms of component and system burn-in times for the two cases of minimal repair at system failure and of component replacement and connection repair at their failure times. The procedure is illustrated with a bridge system and the optimal system burn-in times are obtained for maximizing system reliability. The result suggests that an assumption of minimal repair at system failure may underestimate the optimal burn-in time in practice.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1470-1475
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• 2003

The senses that a doctor can feel is limited in MIS(Minimal Invasive Surgery) which guarantees the fast recovery of the patient and minimal incision for going in and out of instruments through the tissue of the patient. In particular, the surgical robotic teleoperation system developed recently serves with only the information of eyesight and auditory sense. Therefore force-reflection is the most demanded element of the senses in manipulating surgical instruments. In this paper, we designed the Master system and the 2 D.O.F grasper for the robotic teleoperation system(Slave) that has two force sensors on the grasper. Particularly, we focused on serve to master's handle with the contact force between tissue and the grasper of Slave.

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.55-57
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• 1984

• Bulletin of the Korean Mathematical Society
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• v.54 no.3
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• pp.875-894
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• 2017

Let $[n]=\{1,2,{\ldots},n\}$. A set ${\mathbf{A}}=\{A_1,A_2,{\ldots},A_l\}$ is a minimal cover of [n] if ${\cup}_{1{\leq}i{\leq}l}A_i=[n]$ and $$\bigcup_{{1{\leq}i{\leq}l,}\\{i{\neq}j_0}}A_i{\neq}[n]\text{ for all }j_0{\in}[l]$$. Let ${\mathcal{C}}(n)$ denote the collection of all minimal covers of [n], and write $C_n={\mid}{\mathcal{C}}(n){\mid}$. Let ${\mathbf{A}}{\in}{\mathcal{C}}(n)$. An element $u{\in}[n]$ is critical in ${\mathbf{A}}$ if it appears exactly once in ${\mathbf{A}}$. Two minimal covers ${\mathbf{A}},{\mathbf{B}}{\in}{\mathcal{C}}(n)$ are said to be restricted t-intersecting if they share at least t sets each containing an element which is critical in both ${\mathbf{A}}$ and ${\mathbf{B}}$. A family ${\mathcal{A}}{\subseteq}{\mathcal{C}}(n)$ is said to be restricted t-intersecting if every pair of distinct elements in ${\mathcal{A}}$ are restricted t-intersecting. In this paper, we prove that there exists a constant $n_0=n_0(t)$ depending on t, such that for all $n{\geq}n_0$, if ${\mathcal{A}}{\subseteq}{\mathcal{C}}(n)$ is restricted t-intersecting, then ${\mid}{\mathcal{A}}{\mid}{\leq}{\mathcal{C}}_{n-t}$. Moreover, the bound is attained if and only if ${\mathcal{A}}$ is isomorphic to the family ${\mathcal{D}}_0(t)$ consisting of all minimal covers which contain the singleton parts $\{1\},{\ldots},\{t\}$. A similar result also holds for restricted r-cross intersecting families of minimal covers.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.178-183
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• 2001

This study was conducted to determine the optimal extraction condition of temperatures and kinds of extraction solvent, and antimicrobial activity of ethanol extract of Quercus mongolica leaf and organic acid against foodborne microorganisms. The antimicrobial activity of ethanol extract at $60^{\circ}C$ for 6 hour against foodborne microorganisms was stronger than those at $30^{\circ}C\;and\;90^{\circ}C$. Also, the ethanol extract showed stronger antimicrobial activity than those of water and methanol extract. The minimal inhibitory concentrations of the ethanol extract of Quercus mongolica leaf against B. cereus and L. monocytogenes, was $62.5{\sim}125\;{\mu}g/mL$ but, the minimal inhibitory concentration was $250\;{\mu}g/mL$ against S. typhimurium and P. aeruginosa and over $500\;{\mu}g/mL$ against E. coli O157:H7, respectively. The minimal inhibitory concentrations of the lactic, citric, acetic acid and the ethanol extract of Quercus mongolica leaf against B. cereus and L. monocytogenes was 2500, 5000, 1250 and $125\;{\mu}g/mL$, respectively. The combined effect of each organic acid and the ethanol extract against B. cereus was not observed but, synergistic effect was observed against L. monocytogenes. In the meantime, when the ethanol extract was combined with each organic acid at sub-lethal concentration, the combination did not increase the inhibitory effect of the most active single compound alone against E. coli O157:H7, respectively.

• Tuberculosis and Respiratory Diseases
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• v.57 no.5
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• pp.434-438
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• 2004

Background : An excessive endotracheal cuff pressure can cause tracheal injury, and insufficient cuff pressure may not generate an effective cuff seal. The peak inspiratory pressure influences the minimal occlusion pressure of the endotracheal tube cuff. However, the relationship between the minimal occlusion pressure and the tidal volume has not been investigated. This study was conducted to estimate the relationship between the tidal volume and the minimal occlusion pressure of the cuff. Methods : Ten mechanically ventilated patients were included. The minimal occlusion pressure of the cuff was measured using a pressure gauge. The basal tidal volume was increased and decreased as much as 10% whilst maintaining the same peak inspiratory pressure. The, minimal occlusion pressures were then measured in the high and low tidal volume state, respectively. Results : The peak inspiratory pressure was $32.6{\pm}4.72cmH_2O$ and the minimal occlusion pressure was $19.0{\pm}2.26$ mmHg in the basal ventilator setting. There was a significant relationship between the peak inspiratory pressure and the minimal occlusion pressure(r=0.77, p<0.01). The minimal occlusion pressure of the cuff was increased to $20.3{\pm}2.4$ mmHg in the high tidal volume state(p<0.05), and decreased to $16.8{\pm}3.01$ mmHg in the low tidal volume state (p<0.001). Conclusion : The minimal occlusion pressure of the cuff can be influenced by changes in the tidal volume as well as by the peak inspiratory pressure.

• Bulletin of the Korean Mathematical Society
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• v.30 no.1
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• pp.117-124
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• 1993

In this paper, we introduce a concept of quasi $O_{z}$ -spaces which generalizes that of $O_{z}$ -spaces. Indeed, a completely regular space X is a quasi $O_{z}$ -space if for any regular closed set A in X, there is a zero-set Z in X with A = c $l_{x}$ (in $t_{x}$ (Z)). We then show that X is a quasi $O_{z}$ -space iff every open subset of X is $Z^{#}$-embedded and that X is a quasi $O_{z}$ -spaces are left fitting with respect to covering maps. Observing that a quasi $O_{z}$ -space is an extremally disconnected iff it is a cloz-space, the minimal extremally disconnected cover, basically disconnected cover, quasi F-cover, and cloz-cover of a quasi $O_{z}$ -space X are all equivalent. Finally it is shown that a compactification Y of a quasi $O_{z}$ -space X is again a quasi $O_{z}$ -space iff X is $Z^{#}$-embedded in Y. For the terminology, we refer to [6].[6].

• YAKHAK HOEJI
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• v.44 no.4
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• pp.300-307
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• 2000

Expression of xenobiotic-metabolizing enzymes can be altered by xenobiotics, which represents changes in the production of reactive metabolic intermediates as well as toxicities in tissues. Metabolic intermediates derived from xenobiotics are considered to produce the reactive oxygen species including drug free radicals and hydroxyl free radicals, which would be ultimately responsible for drug-induced toxicities. The effects of 1,2-benzothiazine anti-inflammatory agents on the expression of xenobiotic-metabolizing enzymes including major cytochrome P450s, microsomal epoxide hydrolase (mEH) and glutathione S-transferase (GST) were studied in the liver with the aim of providing the part of information on potential production of reactive metabolites and hepatotoxicity by the agents. The synthetic compounds 24, 36 and 39 exhibited anti-inflammatory effects in rats as assessed by the Randall-Selitto method. The anti-inflammatory effect was detected as early as at 30 min after gavaging the agents with the ED5O being noted at 80 mg/kg, which was comparable to that of ibuprofen. Treatment of rats with each compound (100 mg/kg, 3d) resulted in no significant induction in the immunochemically-detectable cytochromes P45O 1A1/2, P450 2B1/2, P45O 2 Cl1 and P45O 2El. Changes in the mEN expression were also minimal, as evidenced by both Western blot and Northern blot analyses. Hepatic GST expression was slightly increased by the agents: GST Ya protein and mRNA expression was ～1.5-fold increased after treatment with compounds 24 and 39, whereas GST Yb1/2 and Yc1/2 mRNA levels were elevated 2- to 3-fold. In summary the effects of the synthetic 1,2-benzothiazines on the expression of major P45O, mEH and G57 were not significant, providing evidence that metabolic activation of the agents, potential drug interaction and hepatotoxicity would be minimal.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.583-588
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• 1990

Glass films in the binary system B2O3-SiO2 and Al2O3-SiO2 were prepared on soda-lime-silica slide glass by the dip-coating technique from TEOS and boric acid or aluminum nitrate. Thickness of the films varying with viscosity and withdrawal speed were measured and effect of composition and firing temperature on the properties such as transmittance and refractive index were investigated. nM2O3.(100-n)SiO2(M=B or Al) films containing up to 20mol% B2O3 and 40mol% Al2O3 were transparent. Maximum transmittance at visible range were obtained for the sample containing 15mol% Ba2O3 and 32.5mol% Al2O3 and heat-treated at 50$0^{\circ}C$, respectively. Refractive index of the film containing 15mol% B2O3 was mininum in the B2O3-SiO2 binary system and minimal refractive index was appeared at the film containing 32.5mol% Al2O3. In IP spectra, addition of B2O3 were increased absorption peak intensity of B-O and Si-O-B bond and addition of Al2O3 were decreased absorption peak intensity of Si-O bond, respectively.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.164-169
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• 1984

Interspecific heterokaryons were obtained between auxotrophic mutants of Pleurotus ostreatus and Pleurotus florida by polyethylene $glycol-Ca^{++}$ induced fusion of somatic protoplasts. The fusion products produced colonies of dense growing mycelium after 10-14 days culture on hypertonic Mushroom Minimal Medium. When they were transferred to Mushroom Minimal Medium plates, the sectors showed normal vegetative morphology but the colonies of irregular shape varied in growth rate. All of the colonies produced fruit body of normal pilei. Some heterokaryon colonies bearing none or only a small amounts of basidiospores were isolated. Fusion products, generally, gave higher basidiocarp yields than the parents.