• ETRI Journal
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• 제35권1호
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• pp.173-176
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• 2013

Existing symmetric cryptography-based solutions against pollution attacks for network coding systems suffer various drawbacks, such as highly complicated key distribution and vulnerable security against collusion. This letter presents a novel homomorphic subspace message authentication code (MAC) scheme that can thwart pollution attacks in an efficient way. The basic idea is to exploit the combination of the symmetric cryptography and linear subspace properties of network coding. The proposed scheme can tolerate the compromise of up to r-1 intermediate nodes when r source keys are used. Compared to previous MAC solutions, less secret keys are needed for the source and only one secret key is distributed to each intermediate node.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5673-5691
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• 2019

Information centric mobile network can significantly improve the data retrieving efficiency by caching contents at mobile edge. However, the cache pollution attack can affect the data obtaining process severely by requiring unpopular contents deliberately. To tackle the problem, we design an algorithm of mitigating cache pollution attacks in information centric mobile network. Particularly, the content popularity distribution statistic is proposed to detect abnormal behavior. Then a probabilistic caching strategy based on abnormal behavior is applied to dynamically maintain the steady-state distribution for content visiting probability and achieve the purpose of defense. The experimental results show that the proposed scheme can achieve higher request hit ratio and smaller latency for false locality content pollution attack than the CacheShield approach and the baseline approach where no mitigation approach is applied.

• 한국대기환경학회지
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• 제5권2호
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• pp.30-35
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• 1989

To effectively develop and evaluate air pollution control measures, health risk rates due to air pollution must be identified. This article describes the application of a visual analysis and an air pollution-health risk model for determining the impacts of carbon monoxide (CO) exposure on angina pectoris patients in a metropolitan area. The procedures used for analyzing the relationship between CO exposure and the related increase in angina angina attacks for stable angina pectoris patients are described through a case study in the city of Seoul, Korea and the findings show that air-pollution-health risk model and visual analysis can be effective tools for environmental decision-makers, allowing air pollution control scenarios to be developed and evaluated for environmental protection. One of the features of this study is to provide a methodology for translating clinical findings into estimates of the relative contributions of air pollution to all causes of a particular disease. Therefore, there must be appropriate recognition of the uncertainties involved in the study.

• Journal of Preventive Medicine and Public Health
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• 제34권1호
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• pp.61-72
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• 2001

Objectives : To evaluate the hypothesis that increasing ambient levels of ozone or particulate matter are associated with increased emergency room visits for asthma and to quantify the strength of association, if any, between these. Methods : Daily counts of emergency room visits for asthma, air quality, and weather data were collected from hospitals with over 200 beds and from monitoring Stations in Seoul, Korea from 1994 through 1997. Daily counts of emergency mom visits for asthma attack were analyzed using a general additive Poisson model, with adjustment for the effects of secular trend, seasonal variation, Sunday and holiday, temperature, and humidly, according to levels of ozone and particulate matter. Results : The association between daily counts of emergency room visits for asthma attack and ozone levels was statistically significant in summer(from June to August), and the RR by unit inclement of 100 ppb ozone was 1.30(95% CI = $1.11\sim1.52$) without lag time. With restriction of the period from April to September in 1996, the RR was 1.37(95% CI = $1.06\sim1.76$), and from June to August in 1995, the RR was 1.62(95% CI = $1.12\sim2.35$). In the data for children$(5\sim14yr)$, the RR was 2.57(95% CI = $1.31\sim5.05$) with restriction of the period from April to September in 1997. There was no Significant association between TSP levels and asthma attacks, but a slight association was seen between PM10 levels and asthma attacks in a very restricted period. Conclusion : There was a statistically significant association between ambient levels of ozone and daily counts of emergency room visits for asthma attack. Therefore, we must make efforts to effectively minimize air pollution, in order to protect public health.

• Journal of Preventive Medicine and Public Health
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• 제39권4호
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• pp.309-316
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• 2006

Objectives: Korean epidemiological studies have used reduced samples according to the subject's characteristics, such as the health services provided, the historical note with asthma, and age, to examine the acute effect of air pollution on asthma using the Korean National Health Insurance records. However, there have been few studies on whether the effects shown in these reduced samples are different from those of all samples. This study compared the effects of air pollution on asthma attacks in three reduced samples with those of entire samples. Methods: The air pollution data for $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, and weather conditions including temperature, relative humidity, and air pressure in Seoul, 2002, were obtained from outdoor monitoring stations in Seoul. The emergency hospital visits with an asthma attack in Seoul, 2002 were extracted from the Korean National Health Insurance records. From these, the reduced samples were created by health service, historical notes with asthma, and age. A case-crossover design was adopted and the acute effects of air pollution on asthma were estimated after adjusting for weather, time trend, and seasonality. The model was applied to each reduced sample and the entire sample. Results: With respect to the health service, the effects on outpatients were similar to those for the total sample but were different for inpatients. These similar effect sizes were also observed in the reduced samples according to the historical note with asthma and age. The relative risks of $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, among the reduced and entire samples were 1.03, 1.04-1.05, 1.02-1.03, 1.04-1.06, and 1.10-1.17, respectively. Conclusions: There was no clear evidence to show a difference between the reduced samples and the entire samples.

• 고신대학교 의과대학 학술지
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• 제33권2호
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• pp.171-180
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• 2018

Objectives: We investigated whether asthma attacks in asthmatic children were caused by short-term exposure to particulate $matter(PM)_{2.5}$. Methods: Subjects were 411 patients who received inhalation therapy in National Fukuoka Hospital, from March to May 2013. All subjects were outpatients. We surveyed the air quality measurement results in the stations closest to the address of the patients. Data were used from the City of Fukuoka website data on air pollution. We carried out a case-crossover study and compared $PM_{2.5}$ concentration between 7 days after asthma attack occurred and the day asthma attack occurred and 1, 2 and 3 days before asthma attack occurred. Results: Highest hourly concentration of the day (OR 1.013, 95%CI 1.000-1.025) showed a significant association with 1 day before $PM_{2.5}$ concentration statistically. And 0-1 year-old infants were more vulnerable to the highest concentration of 1 day before $PM_{2.5}$ concentration(P < 0.05). Average concentration of $NO_2$ and $O_3$ and asthma attack also showed a significant association. Conclusions: Maximal daily $PM_{2.5}$ concentrations within 24 hours prior to the attack affect asthma exacerbation. 0-1 year-old infants are particularly vulnerable to $PM_{2.5}$ concentration. Asthma exacerbation is aggravated by $NO_2$ and $O_3$ concentration on the day of the asthma attack.

• Journal of Preventive Medicine and Public Health
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• 제39권1호
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• pp.81-86
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• 2006

Background: A number of studies have reported associations between the ambient air pollution concentrations and various health outcomes. Especially, ozone is well known for primary risk factor of asthma attacks. The results of a recent study indicate that the size of the effect on health outcomes due to air pollution varied according to several conditions, including age, gender, race and the socioeconomic status. Therefore, this study was conducted to examine the associations of ozone with the childhood asthma hospitalizations as stratified by the socioeconomic status (SES) at the community level in Seoul, Korea, 2002. Methods: SES at aggregated levels was measured on the basis of average regional health-insurance rate per citizen in the area. We applied the generalized additive model to analyze the effect of ozone on asthma after controlling for the potential confounding variables that were capable of influencing the results. Results: Our analysis showed that the number of children who were hospitalized for asthma increased as the SES of the residence area decreased. The estimated relative risks of hospitalization for asthma, as stratified by the SES of the community level, were 1.12 (95% confidence interval 1.00-1.25) in districts with the highest SES levels, 1.24 (95% CI=1.08-1.43) within the moderate SES levels, and 1.32 (95% CI=1.11-1.58) in the districts with the lowest SES levels. Conclusions: Our analysis showed that exposure to air pollution did not equally affect the health status of individuals. This suggests that not only the biological-sensitivity markers, but also the SES of the subjects should be considered as potentially confounding factors.

• Journal of Advanced Research in Ocean Engineering
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• 제4권1호
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• pp.7-15
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• 2018

The submarine is an underwater weapon system which covertly attacks the enemy. Pressure hull of a submarine is a main system which has to have a capacity which can improve the survivability (e.g., protection of crews) from the high pressure and air pollution by a leakage of water, a fire caused by outside shock, explosion, and/or operational errors. In addition, pressure hull should keep the functional performance under the harsh environment. In this study, optimal design of submarine pressure hull is dealt with 7 case studies done by analytic method and then each result's adequacy is verified by numerical method such as Finite Element Analysis (FEA). For the structural analysis by FEM, material non-linearity and geometric non-linearity are considered. After FEA, the results by analytic method and numerical method are compared. Weight optimized pressure hull initial scantling methods are suggested such as a ratio with shell thickness, flange width, web height and/or relations with radius, yield strength and design pressure (DP). The suggested initial scantling formulae can reduce the pressure hull weight from 6% and 19%.

• 정보보호학회논문지
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• 제23권2호
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• pp.319-328
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• 2013

세계 주요 국가들은 전력수요 증가, 환경오염 등의 문제를 해결하기 위해 자국의 전력망을 스마트그리드로 변경하기 위한 노력을 기울이고 있다. 국내에서도 스마트그리드 도입을 위한 다방면의 연구가 진행되고 있다. 그러나 양방향 통신을 적용한 스마트그리드에는 기존 IT에 존재하는 사이버 위협이 적용되어, 국가적 차원에서 사회적 경제적 혼란을 야기할 수 있는 사이버 테러의 위험도 증가하고 있다. 이러한 사이버 공격에 대응하기 위해 사이버 침해사고 발생 시 이에 대한 조사와 이를 분석하고 재발 방지를 위한 노력이 필수적이다. 침해사고에 대응하기 위한 디지털 증거 수집에 대한 연구는 그간 꾸준히 진행되고 있으나 스마트그리드 환경에 적합한 디지털 증거 수집 방안에 대한 연구는 아직까지 미흡하다. 본 논문에서는 스마트그리드 환경에서 필요한 증거 수집 요구사항과 기존까지 연구된 디지털 증거 수집 방안을 분석하여 스마트그리드 환경에 적합한 디지털 증거 수집 기법에 대해 제안한다.

• 대한한의학원전학회지
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• 제23권1호
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• pp.257-277
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• 2010

The purpose of this article is to oversee the theory of Chimibyeong(治未病). The aim of Chimibyeong theory is to prevent disease from occuring, worsening, being delivered and so on. In many books, the word Chimibyeong was used as an alternative name for Yangsaeng(養生) or used as a term of preventing a disease or used as a word meaning treating disease in the early stage. But after the period of "Nangyeong(難經)", people extend the meaning of Chimibyeong to all stages of a disease covering the healthy stage, the early stage, the progressive, and the recovery stage of a disease. Especially in urgent cases when pathogenic factor[邪氣] attacks patient to critical situations, it is also regarded as one way of Chimibyeong to repel pathogenic factor out as soon as possible with proper medicines. These days people suffer from increasing mental stress, lack of rest and human relationships, environmental pollution and chronic diseases and so on, and the situation will grow worse. Many governments employ the health policy where preventing disease takes the highest priority because by doing that they can save a huge budget and minimize the economic and social disorder. In this circumstances the idea of pursuing prevention in the theory of Chimibyeong will help people to maintain healthy conditions.