• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.244-250
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• 2012

The results of analyzing the difference between performances of individual dosimeters on this research subjecting the PLD and TLD, which are the official personal dosimeters, through dosimetry are as follows. After scanning the integral dose using an automatic scanner, the values of two devices that went through dose adjustment process had a statistical difference in TLD and PLD measurements under each filming conditions which were 70kVp, 200mA, 0.012sec and 42kVp, 100mA, and 0.012sec (p<0.001 and p<0.001 respectively). As for the difference of measurement value between DAP and the two particles under 70kVp, 200mA, 0.012sec filming condition, TLD had a value lower than DAP average value by $44.2mGy{\cdot}cm^2$ and PLD had a value of $246.8mGy{\cdot}cm^2$ which was lower than DAP average value by $15.5mGy{\cdot}cm^2$, while under 42kVp, 100mA, 0.012sec filming condition, TLD had a value lower than DAP average value by $17.9mGy{\cdot}cm^2$ and PLD had a value of $82.6mGy{\cdot}cm^2$ which was lower than DAP average value by 7.6$mGy{\cdot}cm^2$. Also, compared to PLD, each of 10 devices measured dose value in TLD had a larger deviation between the particles, and for a reproducibility test which repeatedly measured one particle, PLD had ${\pm}1%$ which was lower than TLD's ${\pm}2%$. As such, PLD had a superior performance result in dose measurement capacities aspect compared to TLD, and therefore we could verify that PLD is more appropriate and advantageous in managing radiation-related task performing worker's personal radiation exposure management in the diagnostic radiation field.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.187-199
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• 2013

Umbrella arch method (UAM) used for improving the stability of the tunnel ground condition has been widely applied in the tunnel construction projects due to the advantage of obtaining both reinforcement and waterproof. The purpose of this study is to develop the evaluation technique of the integrity of bore-hole in UAM by using a non-destructive test and to evaluate the possibility of being applied to the field. In order to investigate the variations of frequency depending on grouted length, the specimens with different grouted ratios are made in the two constraint conditions (free boundary condition and embedded condition). The hammer impact reflection method in which excitation and reception occur simultaneously at the head of pipe was used. The guided waves generated by hitting a pipe with a hammer were reflected at the tip and returned to the head, and the signals were received by an acoustic emission (AE) sensor installed at the head. For the laboratory experiments, the specimens were prepared with different grouted ratios (25 %, 50 %, 75 %, 100 %). In addition, field tests were performed for the application of the evaluation technique. Fast Fourier transform and wavelet transform were applied to analyze the measured waves. The experimental studies show that grouted ratio has little effects on the velocities of guided waves. Main frequencies of reflected waves tend to decrease with an increase in the grouted length in the time-frequency domain. This study suggests that the non-destructive tests using guided ultrasonic waves be effective to evaluate the bore-hole integrity of the UAM in the field.

• Cartoon and Animation Studies
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• s.38
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• pp.177-194
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• 2015

This study that had been conducted two months by a research team of Pusan National University at the request of Korea Manwha Contents Agency in Dec. 2013 is about the statistical analysis on 'Korean Webtoon DB and its Flow Report' which resulted from the complete survey of Korean webtoons which had been published with payment in official media from early 2000 to 2013. Webtoon which means the cartoons published on web has become a typical type of Korean cartoons and has developed into a main industry since 2000s when traditional published cartoons had declined and social environments had changed. Today, it represents cultural contents in Korea. This study collected the webtoons officially published in media with payment, among Korean webtoons having been published from the early 2000s to Jan. Based on the collected data, it analyzed the general characteristics of webtoons, including cartoonists, the number of cartoons, distribution chart of each media, genre, and publication cycle. According to the data analysis and statistics, a great deal of Korean webtoons are still published in main portal websites, but their platform is being diversified and a webtoon's publication cycle tends to be shortened. In terms of genre, traditional popular genres, such as drama, comic, fantasy, and action, are still popular, and the genres of history, sports, and food are on the rise along with a social trend. Regarding webtoon application, such events as relay webtoon and brand webtoon, and a new type of webtoon featuring PPL commercialism appear. Such phenomena can realize the common profits of cartoonists, media, and ordering bodies, and are various trials to test the possibility of webtoons. In addition, what needs to pay attention on in the expansion of webtoons is increasing webtoons for adults. The study subjects are the webtoons published with payment, excluding free webtoons. However, this study failed to collect the webtoons published on the online websites already closed, and the lost information on cartoonists and their lost webtoons, and it is necessary to conduct a complete survey on all webtoons including free ones. Despite the limitations, this study is meaningful in the points that it categorized and analyzed Korean webtoons accoridng to official media, webtoons, cartoonists, and genres and that it provided a fundamental material to understand the current conditions of webtoons. It is expected that this study will be able to contribute to activating more research on webtoons and producing more supplementary data which will be used for the Korean cartoon industry and academia.

• Journal of Yeungnam Medical Science
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• v.10 no.1
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• pp.103-113
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• 1993

This study was conducted to explore the feasibility of using the lead level in the hair of children as a screening test for lead intoxication of children and as an indicator for environmental pollution. Lead concentration of hair was measured for 268 seven to nine-year-old elementary school children in Taegu city (147 children) and Gampo town(121 children). The lead level in hair was measured by atomic absorption spectrophotometer equipped with a graphite furnace atomizer. The following information was obtained for all children: sex, age, father's occupation and smoking habits, kinds of hair cleaner, fingernail biting habits, and status of the child's hands and clothing. The mean lead level in hair was $8.7{\pm}2.9{\mu}g/g$ in the urban area and $7.7{\pm}2.2{\mu}g/g$ in the rural area. There were significant differences between two groups(p<0.01). The difference of lead levels in hair measured by cleanliness of the child's hands(clean: $7.4{\pm}2.7{\mu}g/g$, dirty: $8.2{\pm}2.6{\mu}g/g$) and child's clothing(clean: $8.0{\pm}2.5{\mu}g/g$, dirty: $9.3{\pm}2.6{\mu}g/g$) were statistically significant, but other factors were not significant. In multiple regression analysis, difference of residency and age were significant variables for lead level in the hair of children. These findings suggest that measurement of lead level in the hair is a useful method for the screening of the lead intoxication of children and monitoring environmental conditions.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1905-1919
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• 2000

The main motivation of this research is to develop an intelligent control strategy for Activated Sludge Process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent flow rate, weather conditions, and etc. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP is generally controlled by a PID controller that consists of fixed proportional, integral, and derivative gain values. The PID gains are adjusted by the expert who has much experience in the ASP. The ASP model based on $Matlab^{(R)}5.3/Simulink^{(R)}3.0$ is developed in this paper. The performance of the model is tested by IWA(International Water Association) and COST(European Cooperation in the field of Scientific and Technical Research) data that include steady-state results during 14 days. The advantage of the developed model is that the user can easily modify or change the controller by the help of the graphical user interface. The ASP model as a typical nonlinear system can be used to simulate and test the proposed controller for an educational purpose. Various control methods are applied to the ASP model and the control results are compared to apply the proposed intelligent control strategy to a real ASP. Three control methods are designed and tested: conventional PID controller, fuzzy logic control approach to modify setpoints, and fuzzy-PID control method. The proposed setpoints changer based on the fuzzy logic shows a better performance and robustness under disturbances. The objective function can be defined and included in the proposed control strategy to improve the effluent water quality and to reduce the operating cost in a real ASP.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.541-549
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• 2020

The Drug Delivery System (DDS) is defined as a technology for designing existing or new drug formulations and optimizing drug treatment. DDS is designed to efficiently deliver drugs for the care of diseases, minimize the side effects of drug, and maximize drug efficacy. In this study, the optimization of tripolyphosphate (TPP) concentration on the size of Chitosan nanoparticles (CNPs) produced by crosslinking with chitosan was measured. In addition, the characteristics of Fe₃O₄-CNPs according to the amount of iron oxide (Fe₃O₄) were measured, and it was confirmed that the higher the amount of Fe₃O₄, the better the characteristics as a magnetic drug carrier were displayed. Through the ninhydrin reaction, a calibration curve was obtained according to the concentration of γ-aminobutyric acid (GABA) of Y = 0.00373exp(179.729X)-0.0114 (R² = 0.989) in the low concentration (0.004 to 0.02 wt%) and Y = 21.680X-0.290 (R² = 0.999) in the high concentration (0.02 to 0.1 wt%). Absorption was constant at about 62.5% above 0.04 g of initial GABA. In addition, the amount of GABA released from GABA-Fe₃O₄-CNPs over time was measured to confirm that drug release was terminated after about 24 hr. Finally, GABA-Fe₃O₄-CNPs performed under the optimal conditions were spherical particles of about 150 nm, and it was confirmed that the properties of the particles appear well, indicating that GABA-Fe₃O₄-CNPs were suitable as drug carriers.

• Food Science and Preservation
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• v.17 no.2
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• pp.190-195
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• 2010

Pressure, used as a minimal processing technology in the food industry, is a valuable tool ensuring microbiologically safe, shelf-stable fruit and vegetable production. Pressure could be used to deliver a greater variety of minimally processed products, as demanded by today's consumers. Weevaluated the effect of <400 MPa pressure, applied during chilling, on fresh fruit purees (strawberry, kiwi, aloe, and pomegranate) and vegetable extracts (from carrot and spinach) during cold storage (<$10^{\circ}C$) for 15-20 days. Samples were prepared in a processing facility in which total plate counts of falling and floating bacteria were controlled at $1{\times}100-10^1$ CFU/plate and $1{\times}10^2-10^3$ $CFU/m^3$ under conditions of $21-25^{\circ}C$ and 55-60% relative humidity. The aerobic plate counts of raw materials were less than $1{\times}10^3$ CFU/g. Evaluation parameters included microbiological safety, vitamin content, and sensory qualities. Although the overall quality of non-treated samples deteriorated with storage time at $10^{\circ}C$, samples pressurized at 250-350 MPa at $5-7^{\circ}C$ for 10 min showed less change, with no significant difference in microbiological safety, vitamin content, or sensory quality. The use of pressure extended the shelf-life during storage at $10^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.87-95
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• 2002

The slow degradation rate of sludge in anaerobic digestion is due to rate-limiting step of sludge hydrolysis. To upgrading of sludge hydrolysis and biodegradabiliry, the pre-treatment had been carried out using acidlc (pH 1.5, 3, 4, 5) and alkaline (pH 9, 10, 13), thermal (50, 100, 150, $200^{\circ}C$), and ultrasonic treatment (400W, 20kHz, 15, 20, 25, 30, 40, 50, 60, 90min). In the best conditions of each treatment, the Soluble SCOD Ratio(%)of treated/untreated sample were increased 102% in acid (pH5), 986% in alkali (pH 13), 595% in thermal ($200^{\circ}C$) and 1123% in ultrasonic (35min) treatment. As the result, the ultrasonic treatment was most effective, followed by alkali, thermal, acid treatment. In the effects of total gas productivity in vial test, the thermal ($200^{\circ}C$) pre-treatment was the highest, followed by thermal ($150^{\circ}C$), ultrasonic (90min), alkaline (pH 9), and ultrasonic (50min). We compared untreated samples and the most efficient pre-treatment samples(at $200^{\circ}C$, for 30min) on gas productivity with changes of HRT in continuous experiments IN thermal treated samples were 2.5 times in SCOD, 2 times in soluble protein and 3.3 times high in soluble carbohydrate than untreated ones. In gas productivity, the thermal treated samples were average 2 times high than untreated ones. And HRT 7 days was most effective. followed by HRT 10, HRT 15 days. But The gas productiviry of HRT 2.5 days was less than untreated, the reason of low gas productivity was come from high organic acids accumulation within reactor.

• Sleep Medicine and Psychophysiology
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• v.22 no.1
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• pp.30-34
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• 2015

Obesity hypoventilation syndrome (OHS) is characterized by severe obesity, excessive daytime sleepiness, hypoxemia and hypercapnea. Because OHS mimics pulmonary hypertension or cor pulmonale, clinicians should recognize and treat this syndrome appropriately. A 58-year-old female visited the emergency room because of dyspnea. She was obese and had kyphoscoliosis. The patient also experienced snoring, recurrent choking during sleep and daytime hypersomnolence which worsened after gaining weight in the recent year. The arterial blood gas analysis showed she experienced hypoxemia and hypercapnea not only during nighttime but also daytime. We suspected OHS and the patient underwent polysomnography to confirm whether obstructive sleep apnea was present. During the polysomnography test, sleep obstructive apnea was observed and apnea-hypopnea index was 9.2/hr. The patient was treated with bilevel positive airway pressure therapy (BiPAP). After BiPAP for 4 days, hypoxemia and hypercapnia were resolved and she is currently well without BiPAP. We report a case successfully treated with clinical improvement by presuming OHS early in a patient who had typical OHS symptoms, even while having other conditions which could cause hypoventilation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.116-122
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• 2011

This study was conducted to investigate the microbiological hazard of spoons and their cases carried by nursery school children and to evaluate the reduction effects of washing methods and ultraviolet (UV) treatments against Escherichia coli on the spoon and spoon case. A total of 78 spoons and their cases were sampled to test about total aerobic bacteria, coliform bacteria, Staphylococcus aureus, Bacillus cereus and Salmonella spp. Total aerobic bacteria were detected over 2.7 log CFU/100 $cm^2$ in 20 out of 36 spoons (55.6%), 9 out of 20 zipper-type spoon cases (45.0%) and 13 out of 22 plastic-type spoon cases (59.1%). Coliform bacteria were also detected in 19 out of 36 spoons (52.8%), 14 out of 20 zipper-type spoon cases (70.0%) and 14 out of 22 plastic-type spoon cases (63.6%). The pathogens tested in this study were not found in all samples except for the zipper-type spoon cases which were contaminated with Staph. aureus (2 samples) and B. cereus (3 samples). The results indicated that the sanitary conditions of spoons and their cases should be improved promptly. To evaluate the reduction effects of washing methods and UV treatments against E. coli, the spoons and their cases were treated at different cleaning times with and without soap, and different UV exposure times, respectively. E. coli with initial cell number of 4 log CFU on the spoons and their cases was not detected when they were cleaned at running water for 30 sec after dish sponging with soap for 30 sec. In UV treatments, E. coli with the same level of washing method was not detected after UV exposure for 15 minute in the spoons and their cases. From the results, the washing and UV treatment should be used to control the microbial contamination of spoons and their cases for more than 1 and 15 minutes, respectively.