• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.73-80
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• 2004

Purpose : The serial clinical findings, biochemical results, and serological hepatitis B virus(HBV) markers in Korean children with chronic HBV infection were analyzed to determine the relationships among these factors. Methods : Ninety children have been chosen from those who have visited to the Department of Pediatrics at St. Vincent's Hospital in The Catholic University of Korea from July 1st, 1995 to June 30th, 2000. The sample patients were followed up for over six months. HBV markers and liver function tests were all performed. Results : All children were asymptomatic at presentation. Eighty-three percent of the children had a history of chronic HBV infection in their families. Eighty-one percent were HBeAg positive, 16% were anti-HBe positive, while 3% were all HBeAg and anti-HBe negative. The prevalence of HBeAg among three age groups : 0~5; 6~10; and 11~15 year-old was 90%, 96% and 61% respectively. The prevalence of HBeAg in less than 10 year-old group was significantly higher than 11~15 year-old group(P=0.001). Serum ALT levels were within 40 IU/L in 64% children, 41~80 IU/L in 17%, 81~200 IU/L in 10%, and beyond 201 IU/L in 9%. The percentage of abnormality of ALT levels in HBeAg positive patients was significantly higher than that of HBeAg negative(P=0.036). Eleven of the 73 HBeAg positive children lost their HBeAg and seroconverted to anti-HBe. In these cases, all had transient elevations in ALT levels before HBeAg seroconversions. The annual rates of spontaneous seroconversion of HBeAg and HBsAg were 9.7% and 0.6%, respectively. Conclusion : Recognition of the dynamics of these changes in viral markers and biochemical findings is needed in the selection and evaluation of therapeutic regimens, establishment of treatment, and calling for controlled trials with adequate follow-up. The hepatitis B carrier state may be asymptomatic in children however, continued surveillance of carriers is important to determine the individual adverse prognostic factors of chronic HBV infections.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.997-1008
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• 2023

Ship detection at sea can be performed in various ways. In particular, satellites can provide wide-area surveillance, and Synthetic Aperture Radar (SAR) imagery can be utilized day and night and in all weather conditions. To propose an efficient ship detection method from SAR images, this study aimed to apply the You Only Look Once Version 5 (YOLOv5) model to Sentinel-1 images and to analyze the difference between individual vs. integrated models and the accuracy characteristics by polarization. YOLOv5s, which has fewer and lighter parameters, and YOLOv5x, which has more parameters but higher accuracy, were used for the performance tests (1) by dividing each polarization into HH, HV, VH, and VV, and (2) by using images from all polarizations. All four experiments showed very similar and high accuracy of 0.977 ≤ AP@0.5 ≤ 0.998. This result suggests that the polarization integration model using lightweight YOLO models can be the most effective in terms of real-time system deployment. 19,582 images were used in this experiment. However, if other SAR images,such as Capella and ICEYE, are included in addition to Sentinel-1 images, a more flexible and accurate model for ship detection can be built.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.284-288
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• 2001

Respiratory viruses are one of the most infectious agent in human. Six different respiratory tract viruses were detected from Busan while working on the preventive surveillance in 1997-2000. The isolation rate from suspected specimens were 8.4%. Influenza virus A, B type, parainfluenza virus, adenovirus, mumps virus, and measles virus were examined from throat swabs, serum, and secretions of patients. Influenza A/Sydney/05/97(H3N2)-like, A/Johanesburg/33/94(H3N2)-like, A/Beijing/262/95(H1N1)-like and Influenza B/Beijing/262/95-like, B/Harbin/07/94-like, B/Guangdong/08/93-like were found. Adenovirus serotype 1, 2, 3 and 5 were detected, antibody of mumps both IgM and IgG were shown and outbreaks of measles were confirmed. Different antigenic types of influenza virus were detected every year, one outbreak of parainfluenza in 1999, mumps outbreak in 1999 and 2000, and incidence of measles in 2000 were noticeable. Monthly outbreaks were November through following March with influenza virus, January through June with adenovirus, February through May and December with mumps, April through August and November, December with measles, respectively. The size of isolated viruses were 130 nm with influenza virus B type, non-enveloped, icosahedron with 70 nm with adenovirus, 170 nm with mumps virus and 180 nm with parainfluenza virus in diameter, respectively.

• Neonatal Medicine
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• v.16 no.1
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• pp.55-63
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• 2009

Purpose: This study was conducted to investigate the incidence and clinical manifestations of rotaviral infections in the neonatal intensive care unit (NICU). We also investigated whether neonates referred from other hospitals cause outbreaks of rotaviral infections in the NICU. Methods: Neonates diagnosed wit rotaviral infections in the NICU at Korea University Ansan Hospital between January 2002 and December 2006 were evaluated retrospectively. Results: Of 1,501 neonates admitted to the NICU, the number of rotaviral infections was 94 (6.3%) and the prevalence was 4.9 cases per 1,000-hospital days. Of 223 neonates referred from other hospitals to our NICU, 24 (10.8%) were confirmed to have rotaviral infections at the time of referral. Common symptoms of rotaviral infections were jaundice diarrhea or loose stools, vomiting, fever, apnea, irritability, seizures, and moaning sounds. Necrotizing enterocolitis of stage II or more was diagnosed in 3 premature neonates, accounting for 3.2% of total infected neonates and 6.8% of premature infected patients. There were no statistically significant differences in the prevalence of symptoms between term and preterm neonates, except for jaundice that is more frequent in premature infants. In time series analysis, the admission of neonates who were born at other hospitals and diagnosed with rotaviral infections were associated 1 month later by increased cases of neonates with rotaviral infections who were born at our hospital, whereas new cases of rotaviral infections among inborn neonates were decreased 2 and 4 months later (P<0.05). Conclusion: Rotaviral infections in NICU were not rare and showed vague symptoms. Three cases (3.2%) were diagnosed with stage II or more necrotizing enterocolitis. The referred neonates with rotaviral infections may induce outbreaks in the NICU, therefore awareness and strict surveillance for rotaviral infections should be performed at the time of referral.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.61-66
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• 2003

Objectives: The purpose of this study is to investigate the relationship between the extent of prolongation in P300 latency by sleep deprivation and personality variables. Methods: Eighteen healthy male college students participated in this study. Subjects remained awake for 37 hours under continuous surveillance. In the morning and evening of two consecutive study days, P300 was checked four times. MMPI and STAI-T were checked in the morning of the first day. The 18 subjects were divided into two groups according to their extent of P300 prolongation by sleep deprivation: Group A consisted of short P300 latency prolonged subjects, and group B of long latency prolonged subjects. The MMPI profiles and STAI-T scores of these two groups were compared. Results: Group B showed significantly higher scores in the Mf subscale (t=-2.16, df=16, p=0.046) and Pa subscale (t=-2.61, df=16, p=0.019) than group A. Group B also showed higher F subscale scores at a marginally significant level (t=-2.11, df=16, p=0.052). Conclusion: These results suggest that subjects with higher scores in F, Mf, and Pa subscales tend to have delayed cognitive process and decreased efficiency of mental process by sleep deprivation. It can be hypothesized that individuals who are sensitive, passive, dependent, and easily projecting are susceptible to the deterioration of cognitive function by total sleep deprivation.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.105-110
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• 2006

A three-layer, feed-forward artificial neural network (ANN) with sixteen input neurons, three hidden neurons, and one output neuron was developed to identify the presence of infectious bronchitis (IB) infection as early as possible in laying hen flocks. Retrospective data from flocks that enrolled IB surveillance program between May 2003 and November 2005 were used to build the ANN. Data set of 86 flocks was divided randomly into two sets: 77 cases for training set and 9 cases for testing set. Input factors were 16 epidemiological findings including characteristics of the layer house, management practice, flock size, and the output was either presence or absence of IB. ANN was trained using training set with a back-propagation algorithm and test set was used to determine the network's capability to predict outcomes that it has never seen. Diagnostic performance of the trained network was evaluated by constructing receiver operating characteristic (ROC) curve with the area under the curve (AUC), which were also used to determine the best positivity criterion for the model. Several different ANNs with different structures were created. The best-fitted trained network, IBV_D1, was able to predict IB in 73 cases out of 77 (diagnostic accuracy 94.8%) in the training set. Sensitivity and specificity of the trained neural network was 95.5% (42/44, 95% CI, 84.5-99.4) and 93.9% (31/33, 95% CI, 79.8-99.3), respectively. For testing set, AVC of the ROC curve for the IBV_D1 network was 0.948 (SE=0.086, 95% CI 0.592-0.961) in recognizing IB infection status accurately. At a criterion of 0.7149, the diagnostic accuracy was the highest with a 88.9% with the highest sensitivity of 100%. With this value of sensitivity and specificity together with assumed 44% of IB prevalence, IBV_D1 network showed a PPV of 80% and an NPV of 100%. Based on these findings, the authors conclude that neural network can be successfully applied to the development of a screening model for identifying IB infection in laying hen flocks.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.2
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• pp.3-39
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• 2011

People may operate unmanned aerial vehicles (UAVs or drones) thousands of miles from the drone's location. Drones were first used (like balloons) for surveillance. By 2001, the United States began arming drones with missiles and using them to strike targets during combat in Afghanistan. By mid-2010, over forty states and other entities possessed drones, many with the capability of launching missiles and dropping bombs. Each new development in military weapons technology invites assessment of the relevant international law. This Insight surveys the international law applicable to the recent innovation of weaponizing drones. In determining what international law rules govern drone use, the most salient feature is not the fact that drones are unmanned. The fact drones carry no human operator may be the most important new technological breakthrough, but the key feature for international law purposes is the type of weaponry drones carry. Whether law enforcement rules govern drone use depends on the situation and not necessarily who is operating the drone. Battlefield weapons may also be lawfully used before an armed conflict in the following situations: when initiating self-defense under Article 51 of the United Nations Charter; when authorized by the UN Security Council; when a government seeks to suppress internal armed conflict; and, perhaps, when a state is invited to assist a government in suppressing internal armed conflict. The rules governing resort to force in self-defense are found in Article 51 of the UN Charter and a number of decisions by international courts and tribunals. Commentators continue to debate whether drone technology represents the next revolution in military affairs. Regardless of the answer to that question, drones have not created a revolution in legal affairs. The current rules governing battlefield launch vehicles are adequate for regulating resort to drones. More research must be undertaken, however, to understand the psychological effects of deploying unmanned vehicles and the effects on drone operators of sustained, close visual contact with the aftermath of drone attacks.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.26-32
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• 2017

Enlargement and speed-up of a ship and diversification of ship's type have served to greatly increase the importance of marine transport means. It's reported that accident occurrence frequency of collision is high next to engine damage among the ship accident types, and that the accident ratio according to human factors is also high. In addition, ship accidents come to occur caused by complex cause factors rather than a sole cause factor, it is necessary to investigate the cause factors through the written verdict. This study proposed the cause factors of collision ship accident on the basis of human factors in collision ship accident among the written verdicts provided by the Korean Maritime Safety Tribunal, and inquired into the cause factor and effect through the correlation analysis of accident occurrence factors. Also, this study predicted the collision accident through analyzed the major cause factor of the occurrence at the zero minute when collision on the basis of the time taken from the time point of detecting collision of ships to the time point of collision occurrence. This study used commercial software-Statistical Package for Social Sciences (SPSS Ver21.0) to do correlation analysis. For time analysis, this study analyzed the cause factor and time by analyzing the time taken from the time point of detected ships to the time point of collision occurrence on the basis of the written verdicts. The study analysis showed that there were many cases of collision ship accidents occurrence caused by more than two sorts of cause factors, and that the case (zero minute) where there is no time to spare for collision avoidance accounted for 36.1 %, and negligence in guard or surveillance of the other ship, and sailing while drowsy, or drinking was a contributor to an accident. Poor watch keeping is very strong relationship with pool ready for sail.

• Tuberculosis and Respiratory Diseases
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• v.58 no.4
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• pp.392-398
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• 2005

Background : The last national tuberculosis survey was carried out in 1995. In 2000, the KTBS(Korean Tuberculosis Surveillance System) replaced a previous national survey. However, the KTBS does not show some of the important epidemiological indexes such as the prevalence of positive tuberculosis or the drug resistance rate. The aim of this study was to compare the clinical features of pulmonary tuberculosis patients admitted to a national tuberculosis hospital in 1995 and 2002. From this study, the authors expect to estimate the trend of the clinical features of tuberculosis in Korea even though it can not represent the Korean tuberculosis situation as a whole. Method : A cross sectional analysis of the clinical features for 331 pulmonary tuberculosis in-patients admitted to the National Masan Tuberculosis Hospital as of Dec. 2002, was carried out and these results were compared with those reported in 1995. Results : In comparison with the data reported in 1995, the mean age was increased by 3.6 years ($44.1{\pm}14.6$ vs $47.7{\pm}16.4$, p<0.01). The number of past tuberculosis history and used anti-tuberculous drugs prior to admission decreased from $2.0{\pm}1.7$ and $6.1{\pm}2.3$ to $1.7{\pm}1.8$ and $4.6{\pm}3.6$(p<0.05, p<0.001), respectively. While the resistance rate for anti-tuberculous drugs was similar (81.0% vs 77.6%), the initial resistance rate(10.5% vs 21.4%) and initial MDR rate(2.4% vs 16.5%) increased significantly(p=0.012, p=0.001, respectively). In 1995, the public health communities were in charge of approximately 65% of newly diagnosed tuberculosis cases, but this reduced to 40.5% in 2002(p<0.001). Conclusion : The existing national TB program (NTP) needs to be revised and strengthened in order to cope with the unfavorably changing situation of the domestic TB problem because the number of TB patients has not decreased and the initial resistance rate has increased greatly. Furthermore, the public and private sectors should cooperate each other to control the TB problem effectively because the private sector is now managing more than half of the TB patients.

• Pediatric Infection and Vaccine
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• v.8 no.2
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• pp.150-159
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• 2001

Purpose : We need to reconsider booster vaccination schedule of Japanese encephalitis vaccination. To do that we evaluate the long-term immunogenicity and the incidence of adverse events with inactivated mouse brain derived Nakayama Japanese encephalitis vaccine. Methods : We tested neutalizing antibody for 311 elementary school students by plaque reduction neutralizing test(PRNT) at USAMC-AFRIMS(United States Armed Forces Research Institute of Medical Science/Department of Virology). We evaluated vaccine related adverse events by spontaneous reporting prospectively among 15,487 vaccinees who were vaccinated at public health center and 2,277 elementary school students who were immunized previously by a questionnaire and school health record. Results : According to the time interval from the last booster injection of 311 children, PRNT antibody titers gradually decreased as the interval increased; 239 mIU/mL, 188 mIU/mL, 134 mIU/mL, 49 mIU/mL each at 6, 18, 30, 42 months after the last booster injection. The seropositivity rates were 98%, 99%, 95.6%, 71.4% each at 6, 18, 30, 42 months after the last booster injection. There were 21(0.13%) cases with systemic reactions among 15,487 vaccinees who had visited the hospital by prospective passive reporting system at public health center. According to the questionnaires and school health records in elementary school students, local induration and pain were 17.4% and 14.8%, respectively. Systemic reactions including fever, vomiting, rash were reported in few cases. Conclusion : Biannual booster vaccination that has been recommended so far should not be necessary. Surveillance for adverse events with inactivated mouse brain derived Nakayama vaccine should be strengthened to better assess the number of cases and reactions associated with immunization.