• Journal of Environmental Health Sciences
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• v.39 no.3
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• pp.289-299
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• 2013

Objectives: For the field application of the dielectric barrier discharge plasma reactor, scale-up of the plasma reactor is needed. This study investigated the possibility of inactivation of microorganisms in sewage using pilot multi-plasma reactor. We also considered the possibility of degradation of total organic carbon (TOC) and nonbiodegradable matter ($UV_{254}$) in sewage. Methods: The pilot plasma reactor consists of plasma reactor with three plasma modules (discharge electrode and quartz dielectric tube), liquid-gas mixer, high voltage transformers, gas supply equipment and a liquid circulation system. In order to determine the operating conditions of the pilot plasma reactor, we performed experiments on the operation parameters such as gas and liquid flow rate and electric discharge voltage. Results: The experimental results showed that optimum operation conditions for the pilot plasma reactor in batch experiments were 1 L/min air flow rate), 4 L/min liquid circulation rate, and 13 kV electric discharge voltage, respectively. The main operation factor of the pilot plasma process was the high voltage. In continuous operation of the air plasma process, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal condition of 13 kV were $10^{2.24}$ CFU/mL, 56.5% and 8.6%, respectively, while in oxygen plasma process at 10 kV, residual microorganisms, $UV_{254}$ absorbance and TOC removal rate at optimal conditions were $10^{1.0}$ CFU/mL, 73.3% and 24.4%, respectively. Electric power was increased exponentially with the increase in high voltage ($R^2$ = 0.9964). Electric power = $0.0492{\times}\exp^{(0.6027{\times}lectric\;discharge\;voltage)}$ Conclusions: Inactivation of microorganisms in sewage effluent using the pilot plasma process was done. The performance of oxygen plasma process was superior to air plasma process. The power consumption of oxygen plasma process was less than that of air plasma process. However, it was considered that the final evaluation of air and oxygen plasma must be evaluated by considering low power consumption, high process performance, operating costs and facility expenses of an oxygen generator.

• Journal of Animal Environmental Science
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• v.12 no.2
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• pp.95-100
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• 2006

This study was carried out to develop a continuous process for recovering phosphorus in swine slurry. Magnesium chloride ($MgCl_2$) was used in the test as a magnesium source and the pH was regulated by adding NaOH and aerating. The results showed that the recovery rate of soluble phosphorus (SP) has increased with the molar ratios increased. In case of pH regulated with NaOH, the recovery rates of SP with molar ratio of 1:1.5 were over 95% from both farms. The removal of ammonia-nitrogen was at levels of $4{\sim}9%$. With aeration treatment, the SP recovery rate was 66% and the removal rate of ammonia-nitrogen was 15%. The treatment of NaOH to increase pH showed better SP recovery efficiency than the aeation treatment. However, in case of ammonia-nitrogen removal, the treatment of aeration showed better results than the NaOH treatment.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.291-302
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• 2002

In most of the previous studies, invasive and discrete techniques have been used to monitor the healing process of the gingival graft. However, Laser Doppler Flowmetry(LDF, floLAB(R), Moor Instruments Ltd., England) is a non-invasive technique for measurement of blood flow in the tissue and also allows continuous monitoring. Thus, we tested the usefulness of LDF in monitoring the healing process of free gingival graft at gingival recession. Eleven gingival graft site of 7 patients, including 5 males and 2 females, aged between 21 and 41 years (mean age 28.5) were monitored for the blood flow. The blood flow in gingival graft at coronal site, central site, apical site, mesial site and distal site was measured using LDF. Blood flow was measured at 1- week, 2- week, 3- week and 4- week after gingival graft surgery from 10 a.m. to 2 p.m. Time-course of the healing process was evaluated by statistical analysis using repeated ANOVA and Duncan test. The results were as follows : (1) Blood flow stayed increased for 2 weeks, and then, it was a tendency to decrease. (2) The blood flow at distal site had always higher than mesial site during the measuring periods. (3) The blood flow was high orderly after 1 week ; most coronal site, most apical site, central site. But that was high orderly after 2 week, 3 week, 4 week ; most coronal site, central site, most apical site. In conclusion, LDF was a useful and clinically adaptable method to monitor wound healing process. Our study suggested that it was important to protect surgical site to promote initial wound healing.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.83-94
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• 2016

Performance of absorbent for post-combustion $CO_2$ capture was measured and discussed. Fully saturated fresh absorbent (P2-15F) and absorbents sampled from absorption and regeneration reactor of continuous $CO_2$ capture process, P2-15A, P2-15R, respectively, were used as representative absorbents. Small scale fluidized bed reactor (0.05 m I.D., 0.8 m high) which can measure exhaust gas concentration and weight change simultaneously was used to analyze regeneration characteristics for those absorbents. Exhausted moles of $CO_2$ and $H_2O$ were measured with increasing temperature. $H_2O/CO$ ratio and working capacity were determined and discussed to confirm reason of reactivity decay after continuous operation. Moreover, possibility of side reaction was checked based on the $H_2O/CO_2$ mole ratio. Finally, suitable regeneration temperature range was confirmed based on the trend of working capacity with temperature.

• Journal of Korean Home Economics Education Association
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• v.1 no.1
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• pp.1-17
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• 1989

Present, we cannot expect the maximum studying effect in a home economics and the drill unit of secondary schools because of several problems. Such problems can be enumerated as follows. 1. The explaination of a making process in texts would be difficult for the students who have a poor understanding to grasp. 2. The much effort would be made due to teacher’s repeated exhibition, by which the progress of a text might be unreasonable. 3. The teachers unaccustomed to the drill might treat it carelessly and become to avoid it. 4. The skill to grasp a general work flow might be lack. Baseing on such problems, this researcher did using a medium of Video in teaching method of home economics. For this purpose, the quality of Video Tape would be important. Above all, we made out the script of Video Tape through advices of specialists in Video medium, majors in home economics, and the students teaching of home economics and the concerned persons, by which we recorded a gather skirt, as a finished goods, especially of the characteristics of each kind of a skirt. Next, we recorded and produced the total steps from a preparation of skirt-making to a finishing as using a V.T.R. shot technique. The Video would be screened and the supplemented explaination of a teacher would be added in a step of instruction. In the development of instruction, students would begin the making. The expected effects according to using Video Tape are as follows. 1. The making order of text would be exhibited by a model directly and the explaination of a narrator would be added concurrently, by which students would understand it easily as confirming each step. 2. All students can watch these steps owing to a close up, one of the V.T.R Techniques. Accordingly, the teacher’s efforts would be decreased and the proper progress of a text could be maintained because of no repeated exhibition of a teacher. 3. To the teachers unaccustomed to and interested in a drill, the medium would become a subsidiary means. 4. Study all steps of a making, students would become to understand the general flow of a work. Therefore, it might be possible to generalize another units of a making. However though this study was designed don a basis of such effects, the using effects based on only the existing study results, and was focused on the production of a medium. Because this research would be a teacher and there was noncooperation of secondary schools, it was impossible to experiment in schools, which was the prime limitation of this study. Therefore we should be experiment further for the continuous studying.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.158-166
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• 1999

The purpose of this study was to investigate the correlation between airborne total dust and man-made mineral fibers (MMMF), and to estimate total dust concentration to maintain below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV$^{(R)}$) for the MMMF. The regression coefficients between airborne total dust concentrations and fiber concentrations determined in the industries producing glass fibers, rock wool. refractory ceramic and continuous filament glass fibers products were 0.41, 0.42, 0.20 and 0.19, respectively. The size characteristics of fibers as well as the amounts of contaminated non-fibrous dusts could affect the correlation intensities. When total dust and fiber exposure data were compared with the occupational exposure limits, there was a large gap between two evaluation results. The regression coefficient between total dust and fiber data was increased ($r^2=0.88$) in the process of insulation installation generating in the higher levels of glass or rock wool fibers. In this case, an estimated total dust concentration of glass wool or rock wool fibers complying with the ACGIH TLV (1 f/cc) was $1.7mg/m^3$. In conclusion, the total dust and fibers concentrations was highly correlated at the higher exposure levels so that total dust-monitoring data could be used to control simply and economically and to estimate worker's exposure to fibers.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.110-117
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• 2023

Reconstructing underwater geometry in real time with forward-looking sonar is critical for applications such as localization, mapping, and path planning. Geometrical data must be repeatedly calculated and overwritten in real time because the reliability of the acoustic data is affected by various factors. Moreover, scattering of signal data during the coordinate conversion process may lead to geometrical errors, which lowers the accuracy of the information obtained by the sensor system. In this study, we propose a three-step data processing method with low computational cost for real-time operation. First, the number of data points to be interpolated is determined with respect to the distance between each point and the size of the data grid in a Cartesian coordinate system. Then, the data are processed with a nonlinear interpolation so that they exhibit linear properties in the coordinate system. Finally, the data are transformed based on variations in the position and orientation of the sonar over time. The results of an evaluation of our proposed approach in a simulation show that the nonlinear interpolation operation constructed a continuous underwater geometry dataset with low geometrical error.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.270-279
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• 2014

Microbial community shifts, associated with performance data, were investigated in an anaerobic batch digester treating high-solid food waste under mesophilic conditions using, a combination of molecular techniques and chemical analysis methods. The batch process was successfully operated with an organic removal efficiency of 44.5% associated with a biogas yield of 0.82 L/g $VS_{removal}$. Microbial community structures were examined by denaturing gel gradient electrophoresis. Clostridium and Symbiobacterium organisms were suggested to be mainly responsible for the organic matter catabolism in hydrolysis and acidogenesis reactions. The dynamics of archaeal and methanogenic populations were monitored using real-time PCR targeting 16S rRNA genes. Methanosarcina was the predominant methanogen, suggesting that the methanogenesis took place mainly via an aceticlastic pathway. Hydrogenotrophic methanogens were also supported in high-solid anaerobic digestion of food waste through syntrophism with syntrophic bacterium. Microbial community shifts showed good agreement with the performance parameters in anaerobic digestion, implying the possibility of diagnosing a high-solid anaerobic digestion process by monitoring microbial community shifts. On the other hand, the batch results could be relevant to the start-up period of a continuous system and could also provide useful information to set up a continuous operation.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.29-39
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• 2021

As damages to individuals, private sectors, and businesses increase due to newly occurring cyber attacks, the underlying network security problem has emerged as a major problem in computer systems. Therefore, NIDS using machine learning and deep learning is being studied to improve the limitations that occur in the existing Network Intrusion Detection System. In this study, a deep learning-based NIDS model study is conducted using the Convolution Neural Network (CNN) algorithm. For the image classification-based CNN algorithm learning, a discrete algorithm for continuity variables was added in the preprocessing stage used previously, and the predicted variables were expressed in a linear relationship and converted into easy-to-interpret data. Finally, the network packet processed through the above process is mapped to a square matrix structure and converted into a pixel image. For the performance evaluation of the proposed model, NSL-KDD, a representative network packet data, was used, and accuracy, precision, recall, and f1-score were used as performance indicators. As a result of the experiment, the proposed model showed the highest performance with an accuracy of 85%, and the harmonic mean (F1-Score) of the R2L class with a small number of training samples was 71%, showing very good performance compared to other models.

• Composites Research
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• v.15 no.2
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• pp.32-39
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• 2002

This study focused on the introduction of processing procedure for microcapsules loaded with the healing agent and then microcapsules with the healing agent were manufactured by experiments. The DCPD (dicyclopentadiene) was used for the healing agent and the shell of microcapsules was consisted of urea-formaldehyde resin. The magnitude and the site distribution of microcapsules were measured by a particle size analyzer using laser diffraction technique. Thermal analysis was conducted by using a DSC fur the healing agent, microcapsules without the healing agent, and microcapsules with the healing agent. Also thermal stability was investigated by using a TGA under continuous and isothermal heating conditions far the healing agent, microcapsules without the healing agent, microcapsules with the healing agent. According to the results. microcapsules with the healing agent were verified to be so thermally stable that the healing agent could not evaporate until the shell of microcapsules were burned.