• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1403-1410
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• 2002

Purpose : In previous studies, various risk factors for recurrent febrile seizures have been identified. But none of these risk factors alone could sufficiently discriminate children at high or low risk for recurrent seizures. Therefore, we tried to identify patients at high risk of recurrent febrile seizures by combining risk factors. Methods : Two hundred and four children who had been admitted to our hospital from March, 1997 to July, 1999 with their first febrile seizures were enrolled in our study, and followed up over 2 years. We investigated the recurrence rate according to variables such as sex, age at first febrile seizure, family history of febrile seizures or epilepsy, type of the first seizure, neurologic abnormality and EEG abnormality. Results : Family history of febrile seizures and age at first febrile seizure(<12 months) were significant independent risk factors for recurrent febrile seizures. With these two combined factors, four groups were allocated and the recurrence rate by each group was designated as follows: group with no family history of febrile seizures and age at first febrile seizure ${\geq}12$ months (no risk factor), 43.8%; the group with no family history and age <12 months(one risk factor), 61.7%; group with family history and age ${\geq}12$ months(one risk factor), 64.5%; group with family history and age <12 months(two risk factors), 90.4%. Conclusion : A correlation between numbers of risk factors and recurrence rate was present and the children with a family history of febrile seizures and a young age at onset(<12 months) were regarded as a high risk group of recurrence.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.179-182
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• 2002

본 논문에서는 음성 압축기를 사용하는 디지털 이동통신 환경에서 한글 음성 인식기의 성능을 분석하기 위하여 다양한 표준 음성 압축기를 이용하여 음성 압축기의 구조, 전송률, 전송 채널의 에러율에 대한 성능을 측정하여 비교하였다. 동일한 구조의 음성 압축기에 대하여 전송률의 증가에 따라 음성 인식률이 증가하지만, 음성 압축기의 구조에 따라 동일 전송률에서도 많은 성능 차이가 발생하는 것을 확인하였다. 특히 IS-127 EVRC의 인식 성능이 매우 떨어지는 것을 알 수 있고, EVRC의 잡음 제거기와 가변 전송률에 의하여 음성 인식 성능이 저하되는 것을 확인하였다. 이를 통하여 청취 음질과 음성 인식 성능 사이의 상관 관계가 높지 않는 것을 알 수 있다. 모든 음성 압축기에 대하여 채널 에러율과 음성 인식기의 성능은 매우 밀접한 관계가 있음을 확인하였고, 평균적으로 채널 에러율 $1.0\%$에서 인식률이 $0.6\%$ 감소하고, 에러 $5.0\%$에서 인식률이 $1.8\%$ 감소한다.

• Journal of Teachers' Pension
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• v.5
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• pp.97-133
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• 2020

전략적 자산배분에서 가장 중요한 것은 목표를 결정하는 것이다. 여기서 목표는 자산운용에서 발생하는 향후 포트폴리오의 예상되는 분포와 이에 영향을 받는 조직의 기대효용을 극대화하는 것으로 정의하는 것이 과학적이고 학술적인 방식이다. 실무는 대체로 이러한 방식과 다르다. 예를 들어 기금운용평가의 가이드라인에서는 목표 수익률에 초점을 두고 있다. 특히 기금운용평가에서는 ALM 기반의 목표 수익률 산출을 제안한다. 하지만, 비현실적인 목표 수익률의 산출과 그 의미의 모호성으로 많은 기금들은 이를 적용하지 않고 있다. 본 연구는 이러한 ALM 기반의 목표수익률 설정 및 자산배분의 문제점을 확인하고, ALM 기반 자산배분에 대한 두 가지 대안을 제시한다. 첫 번째, 기금 자산운용의 목표 설정에 대해서는 Doran(1981)의 SMART (Specific, Measurable, Achievable, Relevant, Time-limited) 기준에 따른 목표수립을 제안한다. 두 번째, 목표 수익률 산출에서는 목표기반투자 (Goal based Investing, GBI) 에 따른 목표 수익률 산출 방법을 제시한다.

• Journal of the Korean Child Neurology Society
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• v.26 no.4
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• pp.227-232
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• 2018

Purpose: Febrile seizure (FS) is the most common type of seizure in children between 6 months to 5 years of age. A family history of febrile seizures can increase the risk a child will have a FS. Yet, prevalence of FS regarding external environment has not been clearly proved. This study attempts to determine the association between prevalence of FS and weather. Methods: This study included medical records from the Korea National Health Insurance Review and Assessment Service. Data were collected from 29,240 children, born after 2004, diagnosed with FS who were admitted to one of the hospitals in Seoul, Korea, between January 2009 and December 2013. During the corresponding time period, data from the Korea Meteorological Administration on daily monitoring of four meteorological factors (sea-level pressure, amount of precipitation, humidity and temperature) were collected. The relationships of FS prevalence and each meteorological factor will be designed using Poisson generalized additive model (GAM). Also, the contributory effect of viral infections on FS prevalence and weather will be discussed. Results: The amount of precipitation was divided into two groups for comparison: one with less than 5 mm and the other with equal to or more than 5 mm. As a result of Poisson GAM, higher prevalence of FS showed a correlation with smaller amount of precipitation. Smoothing function was used to classify the relationships between three variables (sea-level pressure, humidity, and temperature) and prevalence of FS. FS prevalence was correlated with lower sea-level pressure and lower humidity. FS prevalence was high in two temperature ranges (-7 to $-1^{\circ}C$ and $18-21^{\circ}C$). Conclusion: Low sea-level pressure, small amount of precipitation, and low relative air humidity may increase FS prevalence risk.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.25-36
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• 2024

Purpose: Tetracycline is not recommended for children under 12 by guideline due to the risk of tooth discoloration. We aimed to assess the incidence of dental discoloration in Korean children prescribed tetracyclines and investigate whether its risk was greater in tetracycline-exposed children than in the general population. Methods: This population-based cohort study using the Health Insurance Review and Assessment service database included children aged 0-12 years exposed to tetracyclines for at least 1 day between January 2008 and December 2020. The primary outcome was the incidence rate of dental discoloration ≥6 months after prescription, and the standardized incidence ratio (SIR) was evaluated as secondary outcome. Results: 56,990 children were included-1,735 and 55,255 aged <8 and 8-12 years, respectively. 61% children were prescribed tetracycline for <14 days with mostly second-generation tetracyclines, doxycycline (61%) and minocycline (35%). The 5- and 10-year cumulative incidence rates of dental discoloration were 4.1% (95% confidence interval [CI], 3.0-5.7%) and 5.7% (95% CI, 4.1% to 7.8%), respectively, in the 0-7 years age group and 0.8% (95% CI, 0.7% to 0.9%) and 1.3 (95% CI, 1.1% to 1.4%), respectively, in the 8-12 years age group. Tetracycline exposure did not increase such risk compared to that in the general population (SIR, 1.08; 95% CI, 0.69 to 1.60). Conclusions: The incidence of dental discoloration was lower than previously suggested. Relieving the age restriction for prescribing tetracyclines may be considered.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.482-490
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• 1999

Objectives : This paper presents the information on the incidence of cancer from the population-based cancer resistry in Kangwha County. Material and methods : This investigation is based on Kangwha cancer registry. The data included cases of cancer diagnosed from 1986 through 1992. The diagnosis of cancer was confirmed by a team of physicians and nurses with the medical records kept in the clinics and hospitals based on the diagnostic criteria recommended by WHO. Home visitings were also made to cancer patients confirmed in every 6 months for the follow up and for the collection of relevant information directly from the patients. Results : A total of 992 cancer cases were registered during 1986-1992. The age-adjusted cancer incidence rate of all site is 201.7 in men and 110.7 in women. The most common cancer is the stomach cancer in both sexes. The age-adjusted incidence rate of the stomach cancer is 65.9 in men and 25.0 in women per 100,000 population. The lung cancer(33.8) and liver cancer(27.7) are next common cancers in men. The cervical cancer(21.8) and lung cancer(8.4) are next in women. Conclusion : The most common cancer is the stomach cancer in both sexes. The annual age-adjusted incidence rate of the stomach cancer is 65.9 in men and 25.0 in women per 100,000 population.

• Journal of the Korean Data and Information Science Society
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• v.23 no.6
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• pp.1183-1194
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• 2012

When it comes to a survey, no answer would occur frequently. Therefore various methods for handling nonresponse have been applied to analyse the survey. In this paper, the ratio of occurrence of two type of nonresponse cases - unit nonresponse and item nonresponse - is presented using previous real survey data, and we compared complete data and data with nonresponse. We suggest the reason of happening of nonresponse and the ratio of nonresponse using data collected through group interviews.

• The Korean Journal of Financial Management
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• v.19 no.1
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• pp.1-32
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• 2002

한국 종합주가지수는 한국증권거래소에 상장된 모든 기업들의 가치 가중치에 의한 포트폴리오의 가격의 시계열이라고 할 수 있다. 따라서 이 지수는 한국 경제의 현재의 활동과 미래의 활동에 대한 예상의 총합의 반영 또는 표상을 표현하는 정보라 할 수 있다. 본 논문에서는 시차변수가 독립변수로 도입될 수도 있으며, 시차변수가 아닌 변수가 독립변수로 도입되는 것이 허용되는 회귀모형을 통하여 구조변화의 회수와 구조변환점을 검정할 수 있는 통계량과 이 통계량의 확률분포를 분석하고 한국 종합주가지수에 적용하여 한국 종합주가 지수의 일별수익률에 구조변화가 발생하였는지의 여부와 발생했다면 발생회수와 변환점들을 발견하는데 그 목적이 있다. 한국 종합주가지수의 일별수익률은 분산의 변화 그리고 평균 및 분산의 동시변화가 1997년 9월 27일에 발생하였다. 자기회귀모형에 의할 때 증권시장의 구조변화는 1999년 11월 16일에 이루어졌다. 평균과 분산의 변화가 일어나 구조변화의 단계를 시작하고 구조변화에 알맞는 환경조성에 2년이 소요된 후에 1999년 11월 16일에 구조변화가 정착되었다. 정착이 이루어진 후에야 비로서 이 두 기간은 서로 다른 경제구조와 증권시장구조가 이루어지고 이에 입각하여 시장의 새로운 운동법칙이 전개되고 있다고 할 수 있을 것이다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.199-201
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• 2012

본 논문은 함정의 대규모 임무지향시스템에서 전술 데이터를 전송할 때 발생할 수 있는 인코더와 디코더 언더플로우를 방지하고, 트래픽이 프레임 별로 역동적으로 발생할 수 있는 환경을 고려하여 트래픽 스무딩을 수행한 전송 시스템에 대하여 설명한다. 기존의 H.263, H.264의 전송 표준 방식인 on-off policing 방법은 인코더의 목표 비트 전송률(Target Bit Rate)에 따라서 일정한 값으로 정해지는 것과 달리, 프레임을 인코딩함으로써 발생한 프레임의 전체 셀 량과 슬라이스 별로 발생하는 데이터 셀의 역동성을 반영하여 프레임마다 전송시간과 전송률을 반영해주면 부드럽게 전술 데이터의 전송이 일어난다. 또한 기존의 on-off policing과 제시한 대규모 임무지향시스템에서의 트래픽 스무딩 알고리듬의 성능을 비교하여 분석한다.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.353-361
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• 2013

To analyze the distribution of earthquake-induced strain data in rock masses, statistical analysis was performed on four-directional strain data obtained from a ground movement monitoring system installed in Korea. Strain data related to the 2011 Tohoku-oki earthquake and two aftershocks of >M7.0 in 2011 were used in x-MR control chart analysis, a type of univariate statistical analysis that can detect an abnormal distribution. The analysis revealed different dispersion times for each measurement orientation. In a more comprehensive analysis, the strain data were re-evaluated using multivariate statistical analysis (MSA) considering correlations among the various data from the different measurement orientations. $T_2$ and Q-statistics, based on principal component analysis, were used to analyze the time-series strain data in real-time. The procedures were performed with 99.9%, 99.0%, and 95.0% control limits. It is possible to use the MSA data to successfully detect an abnormal distribution caused by earthquakes because the dispersion time using the 99.9% control limit is concurrent with or earlier than that from the x-MR analysis. In addition, the dispersion using the 99.0% and 95.0% control limits detected an abnormal distribution in advance. This finding indicates the potential use of MSA for recognizing abnormal distributions of strain data.