• Journal of Korean Society on Water Environment
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• v.33 no.3
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• pp.282-290
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• 2017

A long-term resuspension of small particles, called persistent turbidity, is one of the most important water quality concerns in the dam reservoirs system located in North Han River. Persistent turbidity may incur aesthetic nuisance and harmful effect on the ecosystem health, in addition to elevated water treatment costs for the drinking water supply to the Seoul metropolitan area. These sufferings have been more intensified as the strength and frequency of rainfall events increase by climate change in the basin. This study was to analyze the effect of an extreme turbidity flow event that occurred in 2006 on the serial reservoirs system (Soyang-Uiam-Cheongpyung-Paldang) in North Han River. The CE-QUAL-W2 model was set up and calibrated for the river and reservoirs system using the field data obtained in 2006 and 2007. The results showed that Soyang Reservoir released turbid water, which was classified as the TSS concentration is greater than 25 mg/L, for 334 days with peak TSS of 264.1 mg/L after the extreme flood event (592.7 mm) occurred between July 10 and 18 of 2006. The turbid water departed from Soyang Reservoir reached at the most downstream Paldang Reservoir after about 20 days and sustained for 41 days, which was validated with water treatment plant data. Since the released water from Soyang Reservoir had low water temperature and high TSS, an underflow formed in the downstream reservoirs and vertically mixed at Paldang Reservoir due to dilution by the sufficient inflow from South Han River.

• Journal of Information Technology Applications and Management
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• v.26 no.3
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• pp.99-120
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• 2019

The purpose of this study is to provide information necessary for establishing a new strategy for customer service improvement by deriving factors affecting user satisfaction and continuous use intention of mobile app service user characteristics, system characteristics, and social characteristics. The results of this study are summarized as follows. First, reliability, innovation, familiarity, convenience, and self-efficacy among the characteristics of mobile app are analyzed as factors that have the greatest influence on user's perceived usefulness. Second, convenience, mobility, and visibility are some of the characteristics of mobile app service. Third, identity, security, and expectation agreement among mobile app service characteristics are analyzed as negative factors that do not affect users' perceived usefulness. Fourth, interactivity, familiarity, and self-efficacy among the characteristics of mobile app service were analyzed as positive factors that have the greatest effect on user's perceived ease of use. Fifth, reliability, mobility, visibility, and convenience among mobile app service characteristics are analyzed as factors that have some positive effects on perceived ease of use of app users. Sixth, identity, innovation, and security among the characteristics of mobile app service are negatively influenced by mobile app users' perceived ease of use. Seventh, the perceived usefulness of mobile app users is analyzed as a factor that has a very positive effect on user satisfaction. Eighth, the perceived ease of use of mobile app users is analyzed as a factor affecting perceived usefulness positively. Ninth, the perceived ease and expectation of mobile app users are positively influenced on user satisfaction. The tenth, the perceived usefulness of the mobile app users was analyzed as a factor having a very positive influence on the persistent intention to use. For the eleventh, the perceived ease of use of mobile app users was analyzed as a factor having a positive effect on the persistent intention to use. The twelfth, mobile app user satisfaction was analyzed as a factor having a very positive effect on the persistent intention to use.

• Clinical and Experimental Pediatrics
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• v.55 no.5
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• pp.177-180
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• 2012

OK-432 (picibanil) is an inactivated preparation of $Streptococcus$ pyogenes that causes pleurodesis by inducing a strong inflammatory response. Intrapleural instillation of OK-432 has recently been used to successfully treat neonatal and fetal chylothorax. Here we report a trial of intrapleural instillation of OK-432 in two preterm infants who were born with hydrops fetalis and massive bilateral pleural effusion. Both cases showed persistent pleural effusion, refractory to conservative treatment, up to postnatal days 26 and 46, respectively. An average of 80 to 140 mL of pleural fluid was drained daily. In case 1, the infant was treated with OK-432 during the fetal period at gestation 28 weeks and 4 days of gestation, but showed recurrence of pleural effusion and progressed into hydrops. Within two to three days after OK-432 injection, the amount of pleural fluid drainage was dramatically decreased and there was no reaccumulation. We did not observe any side effects related to OK-432 injection. We suggest that OK-432 should be considered as a therapeutic option in infants who have persistent pleural effusion for more than four weeks, with the expectation of the early removal of the chest tube and a good outcome.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.1
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• pp.22-26
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• 2008

Red long persistent phosphors of $CaZrO_3$ : Pr was synthesized by a solid reaction method. $CaCO_3\;and\;ZrO_2$ were used as hosting materials and Pr was doped as luminescence center element, and $B_2O_3$ was used as flux. The XRD pattern confirmed crystalline phase of the phosphor, and photoluminescence investigation showed emission spectrum at $480{\sim}570nm\;and\;590{\sim}700nm$. Phosphor samples were synthesized with $B_2O_3$ flux concentration of 1, 5, 10%, and luminescent peak of maximum intensity at 494 nm was obtained for 1% $B_2O_3$. Luminescent peak of red color at 620 nm was of highest intensity for 10% $B_2O_3$.

• Journal of the Korean Solar Energy Society
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• v.40 no.5
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• pp.13-22
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• 2020

Day ahead forecast is necessary for the electricity market to stabilize the electricity penetration. Numerical weather prediction is usually employed to produce the solar irradiance as well as electric power forecast for longer than 12 hours forecast horizon. Korea Meteorological Administration operates the UM-LDAPS model to produce the 36 hours forecast of hourly total irradiance 4 times a day. This study interpolates the hourly total irradiance into 15 minute instantaneous irradiance and then compare them with observed solar irradiance at four ground stations at 1 minute resolution. Numerical weather prediction model employed here was produced at 00 UTC or 18 UTC from January to December, 2018. To compare the statistical model for the forecast horizon less than 3 hours, smart persistent model is used as a reference model. Relative root mean square error of 15 minute instantaneous irradiance are averaged over all ground stations as being 18.4% and 19.6% initialized at 18 and 00 UTC, respectively. Numerical weather prediction is better than smart persistent model at 1 hour after simulation began.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1228-1230
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• 2005

This paper deals with design of heater trigger switching in a persistent current system(PCS) by finite element method(FEM) analysis of YBCO coated conductor(CC) tape. Most promising superconducting wire is YBCO coated conductor tape in these days for its high n value and critical current independency from external magnetic field. It is expected to be used many superconducting application such as fault current limiter and cable etc. The superconducting magnet which is operated in persistent current mode in SMES, NMR, MRI and MAGLEV has many advantages such as a high uniformity of a magnetic field and reducing a thermal loss. A PCS system consists of magnet power supply (MPS) which energized current to a magnet, heater, a coated conductor tape for switching, and superconducting magnet. In this paper, the characteristic of thermal quench of the YBCO CC tape and BSCCO tape by heater trigger analyzed by FEM. And optimal length of heater is calculated by temperature and time analysis. This heater trigger analysis is expected to be a basic concept of PCS application design.

• Journal of Chest Surgery
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• v.32 no.12
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• pp.1115-1117
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• 1999

A persistent left superior vena cava draining into the coronary sinus is the most benign and widely encountered abnormality and can easily be explained embryologically as the persistence of the usual pattern of vnous circulation in the embryo,. However a persistent left superior vena cava draining into the left atrium with absent right superior vena cava is an extremely rare anomaly. We report this situation in an infant with tetralogy of Fallot. The most common approach has traditionally been intraatrial baffle repair to create a tunnel to the right atrium or rerouting of the left superior vena cava flow by directly anastomosing the left superior vena cava to the right atrium In the present study the left superior vena cava was transposed to the left pulmonary artery after the correction of tetralogy of Fallot. The most common approach has traditionally been intraatrial baffle repair to create a tunnel to the right atrium or rerouting of the left superior vena cava flow by directly anastomosing the left superior vena cava to the right atrium. In the present study the left superior vena cava was transposed to the left pulmonary artery after the correction of tetralogy of Fallot.

• Annals of dermatology
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• v.30 no.6
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• pp.688-693
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• 2018

Background: There are few pharmacologic options to reduce erythema and flushing in patients with recalcitrant erythematotelangiectatic rosacea (ETR). We previously reported two cases of refractory flushing and erythema of rosacea that were successfully treated with intradermal botulinum toxin injection, and additional research is needed to prove the efficacy and safety of this treatment. Objective: To report the efficacy and safety of botulinum toxin injection as an aid in persistent erythema of rosacea patients. Methods: A total of 20 Korean patients with recalcitrant ETR were enrolled to receive treatment by injection of botulinum toxin. Patients received one treatment of intradermal botulinum toxin injection and were assessed 1, 2, 4, and 8 weeks after treatment. The severity of erythema and telangiectasia was investigated by a non-treating physician, and the Erythema Index (EI) was assessed by mexameter at each visit. Patient satisfaction and any adverse events were also assessed at each visit. Results: 17 patients completed all follow-up visits and were included in the analysis. Intradermal injection of botulinum toxin significantly reduced erythema severity and EI in ETR patients. Patients reported a satisfaction score of $2.94{\pm}0.56$ at 8 weeks after treatment. Except for three patients who discontinued the study early due to inconvenience of facial muscle paralysis, 17 patients participating in the final analysis did not report side effects except injection pain at the time of the procedure. Conclusion: Intradermal injection of botulinum toxin can be used as an effective and relatively safe adjuvant agent for recalcitrant and persistent erythema of ETR patients.

• International Journal of Arrhythmia
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• 제18권2호
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• pp.66-76
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• 2017

Background and Objectives: Although an anterior linear ablation is an effective lesion set in radiofrequency catheter ablation (RFCA) for longstanding persistent atrial fibrillation (L-PeAF), its durability for bidirectional block (BDB) is only about 60% at repeat procedure. We hypothesized that changes in electrocardiogram (ECG) may predict an anterior line block state and the clinical outcome of L-PeAF ablation. Subjects and Methods: We studied 304 L-PeAF patients (77% male, $60{\pm}10yrs$), who consistently underwent RFCA Dallas lesion set (circumferential pulmonary vein isolation, posterior box lesion, and anterior line) protocol with subsequent comparison of pre-procedural and post-procedural P wave axes, and one year follow-up (n=205) sinus rhythm (SR) ECGs. Results: 1. P wave axis shifted inferiorly at immediate post-procedure (p<0.001), and was independently correlated with BDB of anterior line (${\ss}=10.4$, 95% confidence interval [CI] 2.79-17.94, p=0.008). 2. The degree of post-procedural inferior shift of P wave axis did not reflect clinical recurrence within one-year (n=205, p=0.923), potentially due to conduction recovery of an anterior line. However, among 160 patients without clinical recurrence within one-year, P wave axis at one-year ECG was independently associated with very late recurrence of AF after one-year (n=160, hazard ratio [HR] 0.98; 95% CI 0.97-0.99, p=0.001), during $45.6{\pm}16.7$ months of follow-up. 3. Among 22 patients who underwent repeat procedures, P wave axis shift was more significant in patients with maintained BDB of an anterior line than in those without (p=0.015). Conclusion: An inferior shift of P wave axis reflects the achievement and the maintenance of an anterior line BDB, and is associated with better long-term clinical outcome after catheter ablation for L-PeAF based on Dallas lesion set.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.190-193
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• 2019

Inhaled corticosteroids (ICSs) have been widely used as a key medication for asthma control. However, ICSs have been known to cause respiratory infections, such as pneumonia and pulmonary tuberculosis. Consequently, a dilemma exists regarding recommendation of persistent lifetime use of ICSs to mild asthma patients. Short-acting ${\beta}$-agonists (SABAs) have also been widely used for symptom relief. However, SABAs have been reported to increase the risk of asthma-related death, though incidences have been very rare. Consequently, a dilemma exists regarding recommendation of a SABA alone without an ICS or a controller to asthma patients even with very mild disease. In the real world, asthma patients tend to intermittently use ICS and more likely to be dependent on SABA since many patients want immediate relief of their symptoms. Consequently, a dilemma exists regarding the underuse of ICSs but the overuse of SABAs. One strategy for solving the presented dilemma would be identification of patients with asthma who require persistent use of asthma controllers. Such patients, who may be referred to as "persistent controller users," should continuously receive ICSs, even under controlled states of asthma. Another strategy would be a patient-adjusted, symptom-driven, intermittent-to-regular treatment combining low-dose ICS/rapid-onset long-acting ${\beta}$-agonists instead of using a SABA alone or with low-dose ICS for the asthma patients with mild disease. Both of these two strategies could avoid the risky treatment of a SABA alone without an ICS and could reduce the dose of ICS with the maintenance of asthma control.