• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3B
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• pp.212-218
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• 2012

An Internet worm is a self-replicating malware program which uses a computer network. As the network connectivity among computers increases, Internet worms have become widespread and are still big threats. There are many approaches to model the propagation of Internet worms such as Code Red, Nimda, and Slammer to get the insight of their behaviors and to devise possible defense methods to suppress worms' propagation activities. The influence of the network characteristics on the worm propagation has usually been modeled by medical epidemic model, named SI model, due to its simplicity and the similarity of propagation patterns. So far, SI model is still dominant and new variations of the SI model, called SI-style models, are being proposed for the modeling of new Internet worms. In this paper, we elaborate the problems of SI-style models and then propose a new accurate stochastic model using an occupancy problem.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.89-95
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• 1999

This study investigates the population model of the spread of HIV/AIDS which the infection is generated by an infectious individual in a population of susceptible. A mathematical model is presented for the transmission dynamics of HIV infection within the communities of homosexual males. The pattern on the epidemic character of HIV, the causative agent of AIDS, was analysed by the mathematical model of AIDS system which is derived according to the ecological relationship between five epidemilogic states of individuals. The computer simulation was performed using real data and the following conclusions are drawn on the basis of the simulations. 1. The model structure and the algorithm described n the thesis is good. 2. In proportion to increase Ro, the population of AIDS patient increases and the time of its widespread reaches earlier. 3. The AIDS patients will be maximum between 7 and 21 years after an attack of AIDS and widespread between 10 and 20 years. 4. Considering the properties of the incubation periods, the maximum number of infected person is increased, and the attack rate is decreased.

• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.15-22
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• 2013

In clinical study or epidemic research, the $2{\times}2$ frequency table is useful to present a summary statistic The values of four cells in $2{\times}2$ table use to calculate the effect measures such as risk ratio, relative ris ratio or odds ratio. In this paper, we suggest that the improved visualization method using a radar diagram supported by MS-office Excel from the $2{\times}2$ frequency table is able to understand and draw easily betweendiagnosti measures such as sensitivity, specificity, predictivity, and likelihood ratio. We use some numerical example in order to show the usage of the proposed method.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.11a
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• pp.171-172
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• 1996

Cocaine is a powerful reinforcer that has become a popular drug of abuse in man. CNS effects that are related to the abuse of cocaine include feeling of well-being and euphoria. Brain dopamine systems are thought to mediate reinforcement and it is often assumed that cocaine's inhibition of dopamine uptake is the mechanism underlying its reinforcing effects. With increase in cocaine use among general population in recent years, adverse effects of the drug have occurred in all social strata and age groups. Therefore, it has been recognized that the epidemic of cocaine abuse is a growing major concerning public health. One of the most troubling aspects of cocaine abuse is its use by pregnant women. Drug abuse during pregnancy puts two lives at risk. Cocaine produces toxic effects on the fetus at concerntrations that are apparently nontoxic to the mother. Not only does cocaine cross the placenta via diffusion and via rapid penetration to mucous membranes, due to its high lipid solubility, but cocaine can also be found in breast milk, the effects of the cocaine can persist long after the child is born. Although it is known that prenatal cocaine exposure is associated with developmental risk to the fetus ana newborn, few studies have been conducted to assess the mechanisms whereby either short-term or long-term administration of cocaine can exert its harmful effects on the mother or the child. Therefore, it was our great interest to investigate the pharmacological and neurobehavioral changes in offspring that are prenatally exposed to cocaine.

• Pediatric Infection and Vaccine
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• v.2 no.2
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• pp.200-206
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• 1995

Myocarditis refers to inflammation, necrosis, or myocytolysis that may be due to many infectious, connective tissue and many other causes affecting the myocardium or involvement of the endocardium or pericardium. The most common manifestation is congestive heart failure, although arrhythmias and sudden death may be the first sign of myocarditis. Viral myocarditis is typically a sporadic but occasionally epidemic illness, noted as an acute potentially fulminant disease of 1-to 4-wk-old infants, as an acute but more benign myopericarditis of toddlers and young children. The most common casuative agent in viral myocarditis is Coxsackievirus and the outcome of the biopsy-proven chronic dilated cardiomyopathy associated with Coxsackievirus is poor without therapy. Myocarditis may be confirmed by percutaneous endomyocardial biopsy and the viral myocarditis may be diagnosed by the serological viral study with the clinical manifestations. He was admitted for the management of tachyarrhythmias occurred suddenly without prodromal symptoms and signs and diagnosed as viral pancarditis by serological Coxsackievirus study, echocardiogram, chest x-ray, EKG and other clinical manifestations.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.191-204
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• 1986

Leptospira isolated from the patients with so called epidemic pulmonary hemorrhagic fever were comparatively studied with standard strains obtained from ATCC. The specific aim of this study was to clarify the morphologic heterogeneity of the isolates, i. e., coexistence of spiral forms in both handness, right and left, rod and spherical forms in their population by comparing them with those of the ATCC strains. No differences between our strains and ATCC strains were noticed in their growth characteristics, responses to the culture media, temperature, antibiotics and antifungal agents. Furthermore, the morphologic heterogeneity had been repeatedly observed even in cultures of standard ATCC strains, which had been noticed in the cultures of bacteria isolated in this laboratory. The serologic analysis of our isolates demonstrated that the bacteria reacted with L. icterohaemorrhagiae and L. australis regardless their differences in time of isolation(1984, 1985). Thus, it was concluded that the spiral bacteria isolated in this laboratory are Leptospira of a new serovar which still remained to be determined. And the previous reports on the morphology of the Leptospira, which described that the Leprospira population has only spiral forms with right. handed coils might be reconsidered.

• Journal of Preventive Medicine and Public Health
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• v.40 no.6
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• pp.454-460
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• 2007

Objectives : Obesity is currently an epidemic in Korea, and sleep duration is thought to be one of the risk factors for obesity. The objective of this study was to test the hypothesis that short sleep duration is associated with obesity in Korean adults. Methods : The data from the 2001 Korean National Health and Nutrition Survey were used, and 6,174 subjects aged $18{\sim}80$ years were included in the analysis. Sleep duration was measured using information obtained from self-reported questionnaires. Obesity, the main outcome variable, was measured according to body mass index. Multiple regression modeling was used to adjust for potential confounding variables. Results : The study results revealed a negative association between sleep duration and body mass index among Korean adults. These associations persisted after controlling for the potential confounding variables. Conclusions : These findings support the hypothesis that sleep duration is associated with obesity in Korean adults. In addition, these observations support earlier experimental sleep studies and provide a basis for future studies on weight control intervention by increasing the amount of sleep.

• The Plant Pathology Journal
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• v.19 no.6
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• pp.280-283
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• 2003

A soybean-sprout rot epidemic occurred in a mass production soybean sprout factory in 2000 and 2001 in Korea, which caused up to 20% production loss. Among the causal pathogenic bacteria and fungi, Pythium deliense was found to be the dominant pathogen of severe root and hypocotyls rot, particularly in recirculating water system. An average of 90% of the isolated fungi from the rotted sprout on potato dextrose agar were Pythium sp. The fungal density of Pythium in the sampled water was monitored in the recycled water system for 1 year using a selective medium (com meal agar with Pimaricin, 10 mg； Rifampicin, 10 mg； and Ampicillin, 100 mg per 1 liter). The drained water from the soybean-sprout cultivation always had a certain amount of fungus in it. The removal of Pythium from the recycling water system must be thorough, safe, and environment friendly. However, the pathogen in the water was easily found even after ozone and chlorine treatments, which were devised on the recycling system for the removal of microorganisms. 5-$\mu\textrm{m}$ pore size filter was applied and was able to successfully control the disease. As the sprout industry increasingly shifts into mass production, the demand for water will increase continuously. Recycling water for sprout production is eco-friendly. However, a process must be devised to be able to first decompose organic matters before Pythium zoospores are filtered.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.491-495
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• 1998

A fungal disease of the cultivated mushroom, Ganoderma lucidum, caused by Xylogone sphaerospora was epidemic throughout all cultivation areas in Korea which caused a lot of yield losses in the mushroom production. For controlling the disease, the screening of effective fungicides against the pathogenic fungus were conducted. Thirty seven commercially available fungicides were tested for their inhibitory activities on potato dextrose agar media supplemented with these fungicides at various concentrations. Twenty one fungicides significantly inhibited mycelial growth of the pathogen, Xylogone sphaerospora, but 16 fungicides had no inhibitory effect. Among these 21 fungicides, 17 fungicides also inhibited mycelial growth of Ganoderma lucidum as well, but imazalil, procymidone, triforine, and vinclozolin had no inhibitory effects. However, vinclozolin showed no inhibitory effect on mycelial growth of the mushroom even at the concentration of 50 $\mu\textrm{g}$/ml vinclozolin solution for 2 hours, and then the pathogen was inoculated. After two month-cultivation of the mushroom, over 90% of logs treated with vinclozolin without pathogen inoculation produced fruiting bodies. However, fruiting bodies were not produced form the logs inoculated with the pathogen, but not treated with vinclozolin. Fifty seven percent of logs. which were pre-treated with vinclozolin and then inoculated with the pathogen produced fruiting bodies. Based on the results, vinclozolin is effective for the control of yellow disease of the Ganoderma lucidum caused by Xylogone sphaerospora.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.579-582
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• 2009

본 연구는 혈액에서 분리되는 미생물의 균종과 항균제 감수성 검사 결과 양상은 환자의 일반적 특성에 따라 다르므로 혈액배양 결과를 분석한 자료는 감염증 환자의 경험적 치료를 위한 중요한 근거가 되고, 특히 ESBL을 생성하는 균주의 경우 항균제의 사용과도 밀접한 관련이 있어 이 연구를 하게 되었다. 대상은 중부지역 일개대학병원의 입원 및 외래환자의 2004-2006년 혈액배양 결과와 항균제 내성 결과를 분석하였다. 혈액배양은 Bact/Alert 3D (North Carolina, Durham, USA)를 이용하여 성인에서는 Bact/Alert S（Aerobic)(Biomerieux Brazil S.A)와 Bact/Alert SN（Anaerobic)(Biomerieux Brazil S.A) 배지를 사용하였고, 소아에서는 Bact/Alert PF (Biomerieux Brazil S.A)배지를 사용하여 5일간 배양하였고, 항균제 감수성 검사는 자동화 동정 및 감수성 장비인 VITEK (BioMerieux vitek. Hazelwood. Missori. USA)을 이용하였다.