• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.253-266
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• 2020

The extended slip-weakening model was investigated by using a compiled set of source-spectrum-related parameters, i.e. seismic moment M_o, S-wave velocity V_s, corner-frequency f_c, and source-controlled high-cut frequency fmax, for 113 shallow crustal earthquakes (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan from 1987 to 2016. The investigation was focused on the characteristics of stress drop, radiation energy-to-seismic moment ratio, radiation efficiency, and fracture energy release rate, G_c. The scaling relationships of those source parameters were also investigated and compared with those in previous studies, which were based on generally used singular models with the dimensionless numbers corresponding to f_c given by Brune and Madariaga. The results showed that the stress drop from the singular model with Madariaga's dimensionless number was equivalent to the breakdown stress drop, as well as Brune's effective stress, rather than to static stress drop as has been usually assumed. The scale dependence of stress drop showed a different tendency in accordance with the size category of the earthquakes, which may be divided into small-moderate earthquakes and moderate-large earthquakes by comparing to M_o = 10¹⁷~10¹⁸ Nm. The scale dependence was quite similar to that shown by Kanamori and Rivera. The scale dependence was not because of a poor dynamic range of recorded signals or missing data as asserted by Ide and Beroza, but rather it was because of the scale dependent V_r-induced local similarity of spectrum as shown in a previous study by the authors. The energy release rate G_c with respect to breakdown distance D_c from the extended slip-weakening model coincided with that given by Ellsworth and Beroza in a study on the rupture nucleation phase; and the empirical relationship given by Abercrombie and Rice can represent the results from the extended slip-weakening model, the results from laboratory stick-slip experiments by Ohnaka, and the results given by Ellsworth and Beroza simultaneously. Also the energy flux into the breakdown zone was well correlated with the breakdown stress drop, ${\tilde{e}}$ and peak slip velocity of the fault faces. Consequently, the investigation results indicate the appropriateness of the extended slip-weakening model.

• Korean Journal of Agricultural Science
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• v.30 no.1
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• pp.76-88
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• 2003

This study exploits the robot system which is necessary in gene study, bio-technology industry. As well, it can achieve the job of DNA chip manufacturing whose use rate has been increased recently. The robot consists of DNA spotting device for spotting DNA on the silylated slide and well plate, bed for fixing well-plate, washing & drying device of washing and drying the pin part of DNA spotting device, distillation-water vessel, and discharge vessel of wash water. We made the term of sticking DNA to the pin on well plate to be 15 seconds. The spot size of DNA was set to be 0.28 mm on the average by bringing the slide into contact with pin for 1 second. At this rate, if DNA is spotted in the minimum space possible of about 0.32mm, it can stick about 8,100 DNA spots on the well plate. Analyzing the procedure: Movement starts. Pin washes, dries, and smears DNA on the well plate. Spots DNA onto 12 chips takes 2 minutes and 50 seconds.

• Journal of Life Science
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• v.34 no.5
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• pp.320-332
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• 2024

The aims of this study were to compare the differences in hemodynamics between cigarette smoking and using heated tobacco products (HTPs) and to determine the acute effects of using HTPs on cardiac autonomic regulation. Another goal was to examine the acute cardiac autonomic responses when using different tobacco sticks in HTPs. Sixteen healthy male smokers completed an open-label, randomized, crossover trial consisting of non-smoking (NS), cigarette smoking, and the use of two different HTPs (IQOS with HEETS; lil SOLID with Fiit). Sub-trials, which included NS, lil SOLID with Fiit, and lil SOLID with HEET, were performed on eight smokers among the total subjects. Hemodynamic variables, such as systolic blood pressure (SBP) and diastolic blood pressure (DBP), and heart rate variability were measured before, during, and 30 minutes after using each tobacco product. Using HTPs resulted in a significant increase in both SBP and DBP, comparable to smoking cigarettes. Cardiac sympathetic activity significantly increased, and cardiac vagal tone (CVT) significantly decreased after acute exposure to HTP aerosol, similar to the effects of cigarette smoke exposure. Furthermore, differences in the withdrawal of CVT were observed when using different tobacco sticks in the same HTPs. The findings of this study indicate that acute exposure to HTP aerosol increases the hemodynamic burden and disrupts cardiac autonomic balance, similar to exposure to cigarette smoke. Moreover, depending on the type of tobacco stick inserted into the HTP device, acute withdrawal of CVT may have been enhanced.

• Quality Improvement in Health Care
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• v.10 no.2
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• pp.190-203
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• 2003

Background: Dental hygienists are at risk of acquiring infections through exposure to infectious agents. This study explores the frequency of exposure to infectious agents and infection control practices among dental hygienists. Methods: We undertook a cross-sectional survey to examine the exposure to infectious agents and infection control practices among dental hygienists through questionnaire. Data were obtained from 124 dental hygienists attending educational conferences. A multiple logistic regression analysis was conducted to determine the factors that effect infection control practices in relation to age, completion of infection control education, recognition of their own serum hepatitis Ag/Ab status, the number of one day patients, location of clinics, type of clinics, and career years. Result: Of the 124 dental hygienists, 91.7% were exposed to at least one accident such as needle stick injuries during their practices periods. The health screening coverage rate in dental hygienists was 16.5%. The number of one day patients and career years were important in relation to infection control practices among dental hygienists. The adjusted odds ratio estimates for career years were 5.049 times greater(95% Cl 1.238-20.597) for groups with over 4 career years than under 2 career years. That for the number of one day patients were 0.261(95% Cl 0.071-0.955) lower for through 20 up to 30 patients, 0.531(95% Cl 0.102-2.78) lower for through 30 up to 40 patients and 0.498(95% Cl 0.123-2.017) lower for more than 40 patients than under 20 patients. Conclusion: From these results, prevalence of infection control practices among dental hygienists is related to the number of one day patients and career years. Prevention of cross infection and reduction of future transmission should be a priority to dental hygienists for promotion of infection control and further efforts to educate newcomers on infection prevention should be made.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.135-146
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• 2020

To define an interface in a conventional level-set method, an analytical function must be revealed for an interfacial geometry. However, it is not always possible to define a functional form of level sets when interfaces become complex in a Cartesian coordinate system. To overcome this difficulty, we have developed a new level-set formalism that discriminates the interior from the exterior of a CAD modeled interface by parameterizing the stereolithography (STL) file format. The work outlined here confirms the accuracy and scalability of the hydrodynamic reactive solver that utilizes the new level set concept through a series of tests. In particular, the complex interaction between shock and geometrical confinements towards deflagration-to-detonation transition is numerically investigated. Also, a process of flame spreading and damages caused by point source detonation in a real-sized plant facility have been simulated to confirm the validity of the new method built for reactive hydrodynamic simulation in any complex three-dimensional geometries.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.92-98
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• 2015

Background: Varenicline, a selective partial agonist/antagonist of the ${\alpha}4{\beta}2$ nicotinic receptor, has proven effectiveness for smoking cessation by several randomized, controlled trials. Because few studies have evaluated the long-term efficacy of varenicline, we tried to evaluate the smoking status of varenicline users up to 3 years after the initial prescription of the drug. Methods: We interviewed varenicline users who were prescribed the drug from June 2007 to May 2010 by telephone, from June 2010 to May 2011. Results: One-hundred and thirty-three of 250 varenicline users (53.2%) were available for the survey. Seven-day continuous abstinence from smoking was adhered to by 17 of 39 respondents (43.6%) at 1 year, and 11 of 36 (30.6%) and 19 of 58 (32.8%) at 2 and 3 years since the first use of varenicline, respectively. Compared to current smokers, successful quitters were older (55.0 years vs. 49.9 years, p=0.01), had better compliance to the 12-week course (27.7 vs. 9.3%, p=0.01), and had taken varenicline longer (10.1 vs. 5.9 weeks, p=0.01). Fifty-four of 71 current smokers (76.1%) were willing to stop smoking in the near future. The preferred ways to cease smoking were will-power (48.1%), varenicline (25.9%), nicotine replacement therapy (11.1%), and others (14.9%). Conclusion: Smokers should be encouraged to stick to the proven way for recommended period of time for successful cessation of smoking.

• Science of Emotion and Sensibility
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• v.26 no.1
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• pp.65-78
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• 2023

Aircraft are representative of human-machine systems. There is a delay between the human operation and the completion of the machine operation such as when the machine starts to operate and when the force is transmitted to the machine and completed. Time perception is an important component of timing tasks and is known to be affected by the anxiety associated with high arousal. This research verified the impact of weather, flight, and time conditions on the anxiety and time perception of in-service pilots in a virtual reality area. Weather conditions were divided into visual flight weather conditions and very low visibility conditions. Experiments 1 and 2 were performed with different flight and time conditions. In Experiment 1, time perception was measured by employing a button added to the control rod in the scenario of hovering and level flight with relatively little transformed in momentum and little delay. In Experiment 2, time perception was measured in the procedure of naturally taking off the helicopter by employing only the control stick in a takeoff scenario where there was a lot of transformation in momentum and a lot of delays. As a result of the experiment, it was reported that anxiety and heart rate increased in very low visibility conditions In particular, among all flight conditions in Experiments 1 and 2, it was reported that time was overestimated in the scenario of increased anxiety. This outcome can lead to overestimation of time under the impact of anxiety and failure of the timing task, which may lead to challenges in maneuvering and possibly lead to accidents.

• Journal of the Korea Society of Computer and Information
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• v.29 no.4
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• pp.115-123
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• 2024

In this paper, we propose a vibration notification system that combines navigation information and wearable bands to ensure safe driving for the transportation vulnerable. This system transmits navigation driving information to a linked application, converts it into a vibration signal, and provides notifications through a wearable band. Existing navigation systems focus on providing route guidance and location information, so the driver's concentration is dispersed, and safety and convenience are deteriorated, especially for those with mobility impairments, due to standard vision and delayed recognition of stimuli, resulting in an increasingly high traffic accident rate. To solve this problem, navigation driving information is converted into vibration signals through a linked application, and vibration notifications for events, left turns, right turns, and speeding are provided through a wearable band to ensure driver safety and convenience. In the future, we will use cameras and vehicle sensors to increase awareness of safety inside and outside the vehicle by adding a function that provides notifications with vibration and LED when the vehicle approaches or recognizes an object, and we will continue to conduct research to build a safer driving environment. plan.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.619-624
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• 2016

Chlorine dioxide ($ClO_2$) gas treatment (75 ppmv, 30 min) has been suggested to improve the microbial safety of postharvest paprika in a previous study. Based on these results, in this study, an additional combined treatment using low-concentration $ClO_2$ gas-generating sticks (3 ppmv) in paprika samples during storage was carried out at $8^{\circ}C$ and 90% relative humidity to further enhance the quality and reduce the decay rate of paprika for the purpose of lengthy storage. After the combined treatment, the initial populations of total aerobic bacteria as well as yeast and molds in the paprika samples decreased by 3.04 and 2.70 log CFU/g, respectively, compared with those of the control samples, and this microbial inactivation was maintained by the low-concentration $ClO_2$ gas-generating sticks during storage. In particular, the decay rate of samples with combined treatment was significantly lower than that of the control. Vitamin C content, hardness, and color quality parameters of paprika samples were not altered by treatment, while weight loss of the samples treated with the combined $ClO_2$ gas was lower than that of the control during storage. These results indicate that the combination of two different $ClO_2$ gas treatments is effective for retaining the quality of paprika during prolonged storage.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1230-1236
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• 2012

To verify that the electrokinetic remediation is effective for decreasing salinity of fields of the plastic-film house, field tests for physical property, chemical property, and crop productivity of soils have been conducted. The abridged result of those tests is as follows. In the EK treatment, the electrokinetic remediation has been treated at the constant voltage (about 0.8 V $cm^{-1}$) for fields of the farm household. At this time, an alternating current (AC) 220 V of the farm household was transformed a direct current. The HSCI (High Silicon Cast Iron) that the length of the stick for a cation is 20cm, and the Fe Plate for an anion have been spread out on the ground. As the PVC pipe that is 10 cm in diameter was laid in the bottom of soils, cations descend on the cathode were discharged together. For soil physical properties according to the EK treatment, the destruction effect of soil aggregate was large, and the infiltration rate of water was increased. However, variations of bulk density and porosity were not considerable. Meanwhile, in chemical properties of soils, principal ions of such as EC, $NO_3{^-}$-N, $K^+$, and $Na^+$ were better rapidly reduced in the EK treated control plot than in the untreated control plot. And properties such as pH, $P_2O_5$ and $Ca^{2+}$ had a small impact on the EK. For cropping season of crop cultivation according to the EK treatment, decreasing rates of chemical properties of soils were as follows; $NO_3{^-}$-N 78.3% > $K^+$ 72.3% > EC 71.6% $$\geq_-$$ $Na^+$ 71.5% > $Mg^{2+}$ 36.8%. As results of comparing the experimental plot that EK was treated before crop cultivation with it that EK was treated during crop cultivation, the decreasing effect of chemical properties was higher in the case that EK was treated during crop cultivation. After the EK treatment, treatment effects were distinct for $NO_3{^-}$-N and EC that a decrease of nutrients is clear. However, because the lasting effect of decreasing salinity were not distinct for the single EK treatment, fertilization for soil testing was desirable carrying on testing for chemical properties of soils after EK treatments more than two times. In the growth of cabbages according to the EK treatment, the rate of yield increase was 225.5% for the primary treatment, 181.0% for the secondary treatment, and 124.2% for third treatment compared with the untreated control plot. The yield was increased by a factor of 130.0% for the hot pepper at the primary treatment (Apr. 2011), 248.1% for the lettuce at the secondary treatment (Nov.2011), and 125.4% for the young radish at the third treatment (Jul. 2012). In conclusion, the effect of yield increase was accepted officially for all announced crops.