• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.3
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• pp.7-15
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• 2019

Cloud computing markets are rapidly growing as cost savings and business innovation are being carried out through ICT worldwide. In line with this paradigm, the nation is striving to introduce cloud computing in various areas, including the public sector and defense sector, through various research. In the defense sector, DIDC was established in 2015 by integrating military, naval, air and military computing centers, and it provides cloud services in the form of IaaS to some systems in the center. In DIDC and various future cloud defense systems, It is an important issue to ensure availability in cloud defense systems in the defense sector because system failures such as network delays and system resource failures are directly linked to the results of battlefields. However, ensuring the highest levels of availability for all systems in the defense cloud can be inefficient, and the efficiency that can be gained from deploying a cloud system can be reduced. In this paper, we classify and define the level of availability of defense cloud systems step by step, and propose the strategy of introducing Erasure coding and failure acceptance systems, and disaster recovery system technology according to each level of availability acquisition.

• Journal of Technology Innovation
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• v.27 no.2
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• pp.1-36
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• 2019

In line with the international community's movement to reduce greenhouse gas emission, Korea implemented FIT(Feed in Tariff) in 2002 as part of its renewable energy development project. Although the policy had shifted to full-scale RPS(Renewable Portfolio Standards) in 2012, policymakers are still seeking changes due to policy ineffectiveness. While previous studies explain sudden policy changes through external factors, recent research sheds light on internal factors in the process of policy transition. The purpose of this study is to investigate the factors that are responsible for rapidly changing policies in latecomer nations. In order to find this, we look at the case of transition from the FIT to the RPS in Korea's expansion of renewable energy policy. As a result of the research, it is confirmed that the Top-Down decision making system of Korea and the external regulatory change cause rapid policy transition. By looking at these variables, we propose useful implications for policymakers to minimize the policy failure in future policy design and evolution.

• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.15-27
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• 2019

The purpose of this study is to investigate the mechanism about damages occurring at quay wall and backfill in Youngilman Port during Pohang earthquake (M5.4) on November 15, 2017. In the field investigation, the horizontal displacement of the caisson occurred between 5 cm and 15 cm, and the settlement at backfill occurred higher than 10 cm. 2D-effective Stress Analysis was performed to clarify the mechanism for the damage. The input earthquake motion used acceleration ($3.25m/s^2$) measured at bedrock of Pohang habor. Based on a numerical analysis, it was found that the effective stress decreased due to the increase of excess pore pressure in the backfill ground and the horizontal displacement of the caisson occurred by about 14 cm, and the settlement occurred by about 3 cm. In backfill, the settlements occurred between 6 cm and 9 cm. This is similar to field investigation results. Also, it was found that the backfill soil was close to the Mohr-Coulomb failure line due to the cyclic loading from the effective stress path and the stress-strain behavior. It may be related to decreasing of bearing capacity induced by the reduction of effective stress caused by the increase of the excess pore water pressure.

• Journal of Rhinology
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• v.25 no.2
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• pp.75-79
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• 2018

Background and Objectives: To investigate the common site of recurrent epistaxis after initial intervention such as packing and cauterization had failed and to evaluate the efficacy of surgical endoscopic electrocautery. Subjects and Method: Retrospective review of 47 patients with recurrent and uncontrolled idiopathic epistaxis between October 1995 and March 2016. All patients underwent endoscopic examination in the operating room after hospitalization. We performed electrocautery when a bleeding site was found. Results: The most common sites of bleeding were the inferior meatus (28%), sphenoethmoid recess (23%), superior septum around the olfactory cleft (13%), and the posterior end of the middle turbinate (15%). There was no serious complication during the one week after surgery. In 46 (98%) patients, refractory epistaxis was successfully controlled. One patient had recurrent epistaxis after electrocautery and underwent endoscopic sphenopalatine artery ligation. Conclusion: In patients with refractory idiopathic epistaxis after failure of first-line treatment, endoscopic examination through a surgical approach and electrocautery for suspected bleeding are effective.

• Pediatric Infection and Vaccine
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• v.29 no.2
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• pp.96-104
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• 2022

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory bone disorder presenting with sterile osteomyelitis, most often presenting in childhood. Although the etiology is understood incompletely, its association with other auto-inflammatory diseases including inflammatory bowel disease (IBD); psoriasis; Wegener's disease; arthritis; and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome suggests that dysregulated innate immunity may play an important role in the pathogenesis. We report a case of a 13-year-old boy with CRMO associated with Crohn's disease (CD) successfully treated with infliximab after failure of non-steroidal anti-inflammatory drug (NSAID) treatment. He initially was diagnosed with CRMO based on symmetric and aseptic bone lesions with no fever, lack of response to antibiotic treatment, vertebral involvement, and normal blood cell counts. Despite five months of NSAID treatment, his musculoskeletal symptoms were aggravated, and he developed gastrointestinal symptoms. Finally, he was diagnosed with CRMO associated with CD. Due to the severity of symptoms, infliximab was initiated and produced symptom improvement. This case supports infliximab as another choice for treatment of bowel symptoms in addition to the bone and joint symptoms of CRMO when other first-line treatments are ineffective.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.101-109
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• 2022

This study describes the results of model experiment to analyze the effect of backfill material types on the behavior of underground facility. In the model experiment, backfill materials around the existing underground facility were applied with soil (Jumunjin standard sand) and CLSM. The displacement of underground facility was analyzed for each excavation stage considering the separation distance between the excavation surface and the backfill area based on the experimental results. When soil was applied as a backfill material, the soil on the back of the excavation surface collapsed by excavation and formed an angle of repose, and the process of slope stability was repeated at each excavation stage. In addition, the displacement of underground facility began to occur in the excavation stage that the failure line of soil passes the installation location of the underground facility. When CLSM was applied as a backfill material, there was almost no horizontal and vertical displacement of the ground regardless of the separation distance from the excavation surface even when excavation proceeded to the backfill depth. Therefore, this result showed that it can have a resistance effect against the lateral earth pressure generated and the collapse of the original ground by adjacent excavation, if a backfill material with high stiffness such as CLSM is applied.

• Smart Structures and Systems
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• v.29 no.4
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• pp.625-640
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• 2022

Maglev rail joints are vital components serving as connections between the adjacent F-type rail sections in maglev guideway. Damage to maglev rail joints such as bolt looseness may result in rough suspension gap fluctuation, failure of suspension control, and even sudden clash between the electromagnets and F-type rail. The condition monitoring of maglev rail joints is therefore highly desirable to maintain safe operation of maglev. In this connection, an online damage detection approach based on three-dimensional (3D) convolutional neural network (CNN) and time-frequency characterization is developed for simultaneous detection of multiple damage of maglev rail joints in this paper. The training and testing data used for condition evaluation of maglev rail joints consist of two months of acceleration recordings, which were acquired in-situ from different rail joints by an integrated online monitoring system during a maglev train running on a test line. Short-time Fourier transform (STFT) method is applied to transform the raw monitoring data into time-frequency spectrograms (TFS). Three CNN architectures, i.e., small-sized CNN (S-CNN), middle-sized CNN (M-CNN), and large-sized CNN (L-CNN), are configured for trial calculation and the M-CNN model with excellent prediction accuracy and high computational efficiency is finally optioned for multiple damage detection of maglev rail joints. Results show that the rail joints in three different conditions (bolt-looseness-caused rail step, misalignment-caused lateral dislocation, and normal condition) are successfully identified by the proposed approach, even when using data collected from rail joints from which no data were used in the CNN training. The capability of the proposed method is further examined by using the data collected after the loosed bolts have been replaced. In addition, by comparison with the results of CNN using frequency spectrum and traditional neural network using TFS, the proposed TFS-CNN framework is proven more accurate and robust for multiple damage detection of maglev rail joints.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.103-112
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• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Biomolecules & Therapeutics
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• v.32 no.5
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• pp.647-657
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• 2024

Gefitinib is the well-tolerated first-line treatment of non-small cell lung cancer. As it needs analgesics during oncology treatment, particularly in the context of the coronavirus disease, where patients are more susceptible to contract high fever and sore throat. This has increased the likelihood of taking both gefitinib and antipyretic analgesic acetaminophen (APAP). Given that gefitinib and APAP overdose can predispose patients to liver injury or even acute liver failure, there is a risk of severe hepatotoxicity when these two drugs are used concomitantly. However, little is known regarding their safety at therapeutic doses. This study simulated the administration of gefitinib and APAP at clinically relevant doses in an animal model and confirmed that gefitinib in combination with APAP exhibited additional hepatotoxicity. We found that gefitinib plus APAP significantly exacerbated cell death, whereas each drug by itself had little or minor effect on hepatocyte survival. Mechanistically, combination of gefitinib and APAP induces hepatocyte death via the apoptotic pathway obviously. Reactive oxygen species (ROS) generation and DNA damage accumulation are involved in hepatocyte apoptosis. Gefitinib plus APAP also promotes the expression of Kelch-like ECH-associated protein 1 (Keap1) and downregulated the antioxidant factor, Nuclear factor erythroid 2-related factor 2 (Nrf2), by inhibiting p62 expression. Taken together, this study revealed the potential ROS-mediated apoptosis-dependent hepatotoxicity effect of the combination of gefitinib and APAP, in which the p62/Keap1/Nrf2 signaling pathway participates and plays an important regulatory role.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.1 no.1
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• pp.37-44
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• 1998

Purpose: This study aimed at evaluating the therapeutic outcome, cost effectiveness and recurrence rate in children with H. pylori infection after the treatment using various medications. Methods: Seventy five children (mean age $11.4{\pm}2.5$ years) were given an endoscopy with biopsy and H. pylori status assessed by CLO test and histologic examination (Warthin Starry stain). Children were given one of following medications such as DA ($Denol^{(R)}$ and amoxycillin), OA (omeprazole and amoxycillin), DC ($Denol^{(R)}$ and clarithromycin) as primary treatment. And one of following medications such as DAM ($Denol^{(R)}$, amoxycillin and metronidazole), DC, OA, OC (omeprazole and clarithromycin) were used in children who failed the eradication of H. pylori. Results: The endoscopic diagnoses were: nodular gastritis (46 cases), gastric ulcer (9), duodenal ulcer (6), superficial gastritis (6), and normal (8). H. pylori eradication rate was 91% (63 of 69 children) on 4 weeks course of DA, 50% (1 of 2 cases who had treatment failure on DA) on DAM, and 75% (3 of 4 cases who treated on DC primarily) and 50% (1 of 2 cases who had treatment failure on DA) on DC, and 100% on OA (all of 2) and on OC (all of 1 who failed on DA). In 3 of 7 children in whom H. pylori had not been eradicated by primary medications (DA 6 and DC 1 case), H. pylori was re-eradicated by secondary medications (DA 1, DAM 1 and DC 1 case). But in remaining 4 cases, H. pylori infection persisted. Reinfection of H. pylori was found in 4 of 75 children between 3 months and 3 years after completion of the treatment of DA, yielding recurrence rate of 5.3%. In 2 of 4 cases who had relapsed, H. pylori was re-eradicated by secondary medications (OC 1 and DA 1 case). But in remaining 2 cases, H. pylori infection persisted. Conclusion: These results suggest that dual therapy with $Denol^{(R)}$ and amoxycillin is the effective medications in treating H. pylori infection in children. Concerning the cost effectiveness, it can be recommended as first line treatment of choice as well.