• 한국산업보건학회지
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• 제6권1호
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• pp.67-76
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• 1996

This study was performed to estimate total dust concentrations and particle size distribution of wood dust in the furniture and sawmill industries. To compare total wood dust concentrations, two samplers recommended by the American Conference of Governmental Industrial Hygienists and by the National Institute for Occupational Safety and Health were used. Concentration data were analyzed by paired-t tests using the SAS program and two parameters of the particle size distributions were determined by histogram. The results were as follows: 1. Particle size distributions showed a unimodal pattern in cutting and a bimodal in sanding operations. Mass median aerodynamic diameters(MMAD) were $17.35{\mu}m$ in cutting, and $1.39{\mu}m$ for small mode and $18.89{\mu}m$ for large mode in sanding operations. The proportions of particle size larger than $9.8{\mu}m$ estimated by the impactor were 61.16 % in cutting and 62.33 % in sanding operations, respectively. 2. The average personal total dust concentrations measured by IPM sampler were $17.12mg/m^3$ (GSD=1.45) from indoor samples, $2.97mg/m^3$(GSD=1.90) from outdoor samples in cutting, and $8.01mg/m^3$(GSD=1.58) from sanding operation. And those of by 37 mm closed-face cassette were $9.12mg/m^3$(GSD=1.46), $1.06mg/m^3$(GSD=1.99) from cutting, and $3.32mg/m^3$(GSD=2.16) from sanding operations. 3. The average area total dust concentrations measured by IPM sampler were $1.88mg/m^3$(GSD=2.04) from indoor cutting, $4.76mg/m^3$(GSD=2.83) from indoor sanding operations. And those of by 37mm closed-face cassette were $0.49mg/m^3$(GSD=2.34) from cutting, and $1.32mg/m^3$(GSD=3.03) from sanding operations. 4. The ratio of personal total dust concentrations measured by 37 mm closed-face cassette to those by IPM sampler were 35.7 %, 53.3 % from cutting, and 41.4 % from sanding operations. 5. The ratio of area total dust concentrations measured by 37 mm closed-face cassette to those by IPM sampler were 26.1 % from cutting, and 27.7 % from sanding operations. 6. A statistically significant difference of total dust concentrations between the 37 mm closed-face cassette and the IPM sampler was found.

• Parasites, Hosts and Diseases
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• 제36권4호
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• pp.241-248
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• 1998

1993년 외국여행 경험이 없는 말라리아 환자가 발견된 이래 1997년까지 총 2,198명의 환자가 발생하였다. 대부분은 휴전선 근처에서 복무한 군인이었으며, 민간인 환자는 총 650명으로 1994년 3례, 1995년 19례, 1996년 71례, 1997년 557례였다. 그 중 239명은 경기도의 파주, 연천, 김포, 강화, 동두천 및 강원도 철원에서 복무한 경험이 있는 제대군인이었으며, 308명은 유행지역에 거주하는 주민이었다. 72명은 모기 활동기에 유행지역을 방문한 적이 있었으며, 32명은 유행지역에 간 적이 없는 사람이었다. 전체적으로 보아 20대 남자가 가장 많았다. 연중 말라리아 발생지수는 높지 않았지만 1993년 이후 유행지역에서 꾸준히 증가하였다. 한국에서 말라리아는 일년 내내 발생하였으며, 8월에 가장 많았다. 제대군인들의 경우 153일에서 452일에 달하는 지연형 잠복기를 나타냈다. 발병에서 진단에 이르는 시간은 1995년 23.6일에서 1997년 13.7일로 단축되었다. 삼일열말라리아의 발생이 휴전선 부근에서 시각되어 일부 지역에서는 이미 정착되었을 가능성이 높다.

• Journal of Preventive Medicine and Public Health
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• 제14권1호
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• pp.43-51
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• 1981

The objective of the study is to measure the changes in measles infection and measles vaccination rates for the past 10 years in a rural area, Kang Wha. The study population were the entire children who were born between 1971 and 1950 in three townships (Sunwon, Naegae, Buleun) in Kangwha County. Two interview surveys were carried out during the 10 years of period, one in 1977 and the other in 1981. The data were collected by Family Health Workers through interview with structured questionnaires. The diagnosis of measles was mainly based on histories, symptoms and sighs of the disease. If a mother had reported measles history of her child, a public physician reviewed and decided the final diagnosis of the reported case. A retrospective cohort observation was done in order to see the trends of measles infections and measles vaccinations. The major findings were as follows; 1. The 5 year prevalence rate of measles vaccinations was 51.3% between 1971 and 1975 and 71.9% between 1976 and 1980 respectively. The difference between two periods was statistically significant (P<0.05). The secular trend of measles vaccinations showed increasing tendency from 1971 to 1978 and since then kept maintained. 2. In the birth cohort analysis of measles vaccinations, the vaccination rates, in general, were higher in the later cohort groups than that of earlier cohort groups. 9. The 5-year experience rates for measles infections were 24.3% between 1971 and 1975 and 17.2% between 1976 and 1980 respectively. This difference was statistically significant(P<0.05). The secular trend of experience rates for measles infections showed decreasing tendency from 1971 to 1980 except an outbreak in 1976. 4. The birth cohort analysis of experience rates for measles infections showed that the rate was higher in the later cohort groups than that of the earlier cohort groups. This decreasing tendency was prominent between $1973{\sim}1974$ and $1976{\sim}1977$. 5. The distribution of age specific incidence rates for measles infections showed unimodal curve with the peak at the age of 12 to 18 months. This findings were same in both two surveys. 6. Seasonal variations of the measles infections showed two peaks, one major peak in March through May and the another minor peak in September through December. 7. The 5-year reduction rate for measles infections among those vaccinated was 90.4% between 1971 and 1975 and 88% between 1976 and 1980.

• 한국재료학회지
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• 제10권12호
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• pp.845-852
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• 2000

국내산 kaolinite를 소성한 다음 실리카를 선택적으로 추출하여 중기공성 ${\gamma}-Al_2O_3$를 제조하였다. $1000^{\circ}C$에서 24시간 소성된 kaolinite는 소량의 무정형 실리카와 ${\gamma}-Al_2O_3$으로 이루어진 스피넬 상의 미세구조로 전이되었음을 확인하였다. 다공성 ${\gamma}-Al_2O_3$는 $25~90^{\circ}C$의 반응온도, 0.5~4h의 추출시간 및 1~8M의 KOH 농도범위에서 무정형 실리카를 선택적으로 용해하여 제조할 수 있었다. $90^{\circ}C$, 1시간 및 4M의 KOH 농도조건에서 얻어진 ${\gamma}-Al_2O_3$는 약 $40~80{\AA}$ 정도의 매우 좁은 하나의 기공크기 분포를 가지고 있었으며, mesopore의 기공이 많이 생성되었다. 비표면적은 $250\textrm{m}^2/g$이고, 총 기공부피는 $0.654\textrm{cm}^3/g$로 나타났다.

• Journal of Ecology and Environment
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• 제43권1호
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• pp.43-60
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• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

• 대한수의학회지
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• 제9권1호
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• pp.1-9
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• 1969

The experimental studies were performed to observe the characteristics of the myelinated nerve fibers of the tradiaphragmatic branches of phrenic nerves in dog In the work to be reported five mixed breed Korean dog were used, they were one year old and he body eights were about 12 Kgm. in average with healthy conditions. The specimens (nerve) were taken at the point of 1.5 cm posterior part from the left and right phrenic nerves entrance to the diaphragm, and the dorso-lateral and dorso-medial branches of phrenic nerves vere also, taken at the point of 0.5 cm distal part from their branching portion. The specimens were fixed for 24 hrs. in Flemming's solution, and embedded in paraffin. The paraffin section. were cut at 6 microns and stained with Walter's modification of Weigert-pal method for the myelinated fibers. Microphotographs were taken and enlarged into 750 times of the actual size, and the diameter of the photographic images of the myelinated fibers were measured by the scale on the transparent Percepex Plate. The following conclusions were made: 1. The percentage of distribution of the several intradiaphragmatic branches of phrenic nerves were as follows. Ventral branches were 34.97%, lateral branches were 37.90%, dorsal branches were 27.13%, and the dorsal branches were branched again into dorso-lateral branches(54.22%) and dorso-medial branches (45. 78%). 2. The mean value and S.D. of the total numbers of the myelinated nerve fibers at the left ventral branches were $490.80{\pm}12$, and at the right ventral branches were $486.6{\pm}13$. Total average cross sectional area on the left ventral branches were 38,000. $6{\pm}136{\mu}^2$, and the right ventral branches were $37,150.2{\pm}1.782{\mu}^2$. 3. The mean value and S.D. of the total numbers of the myelinated nerve fibers at the left lateral branches were $533.8{\pm}8$, and at the right lateral branches were $525.6{\pm}7$. Total average cross sectional area of the left lateral branches were $41,582{\pm}1,170{\mu}^2$, and the right lateral branches were $40,454.8{\pm}812{\mu}^2$. 4. The mean value and S.D. of the total numbers of the myelinated nerve fibers at the left dorsal branches were $378.2{\pm}14$, and at the right dorsal branches were $380.2{\pm}8$. Total average cross sectional area of the left dorsal branches were $27,771{\pm}1,256{\mu}^2$, and the right dorsal branches were $27,507.2{\pm}645{\mu}^2$. 5. The mean value and S.D. of the total numbers of the myelinated fibers at the left dorso-lateral branches were $205.4{\pm}15$, and at the right dorso-lateral branches were $210.6{\pm}17$. Total average cross sectional area of the left dorso lateral branches were $15,354. 8{\pm}1,519{\mu}^2$, and the right dorsal branches were $15,887{\pm}1,297{\mu}^2$. 6. The mean value and S.D. of the total numbers of the myelinated nerve fibers at the left dorso-medial branches were $175{\pm}14$, and at the right dorso-medial branches were $176.2{\pm}17$. Total average cross sectional area of the left dorso-medial branches were $13,037.4{\pm}944{\mu}^2$, and at the right dorso-medial branches were, $13,103{\pm}1,373{\mu}^2$. 7. The highest frequent distribution of the intradiaphragmatic branches of phrenic nerves were found in the $10-12{\mu}^2$ groups, and they were almost 30% of the total groups. 8. The largest fibers diameter were in the $14-16{\mu}^2$ groups, and these were shown the lowest frequent distribution. 9. The largest cross sectional area of the intradiaphragmatic branches of phrenic nerves were found in the $10-12{\mu}^2$ groups. 10. All of the intradiaphragmatic branches of phrenic nerves were unimodal which has a peak in the $10-12{\mu}^2$ groups.

• 지능정보연구
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• 제27권3호
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• pp.57-73
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• 2021

ICT 인프라의 이상탐지를 통한 유지보수와 장애 예방이 중요해지고 있다. 장애 예방을 위해서 이상탐지에 대한 관심이 높아지고 있으며, 지금까지의 다양한 이상탐지 기법 중 최근 연구들에서는 딥러닝을 활용하고 있으며 오토인코더를 활용한 모델을 제안하고 있다. 이는 오토인코더가 다차원 다변량에 대해서도 효과적으로 처리가 가능하다는 것이다. 한편 학습 시에는 많은 컴퓨터 자원이 소모되지만 추론과정에서는 연산을 빠르게 수행할 수 있어 실시간 스트리밍 서비스가 가능하다. 본 연구에서는 기존 연구들과 달리 오토인코더에 2가지 요소를 가미하여 이상탐지의 성능을 높이고자 하였다. 먼저 다차원 데이터가 가지고 있는 속성별 특징을 최대한 부각하여 활용하기 위해 멀티모달 개념을 적용한 멀티모달 오토인코더를 적용하였다. CPU, Memory, network 등 서로 연관이 있는 지표들을 묶어 5개의 모달로 구성하여 학습 성능을 높이고자 하였다. 또한, 시계열 데이터의 특징을 데이터의 차원을 늘리지 않고 효과적으로 학습하기 위하여 조건부 오토인코더(conditional autoencoder) 구조를 활용하는 조건부 멀티모달 오토인코더(Conditional Multimodal Autoencoder, CMAE)를 제안하였다. 제안한 CAME 모델은 비교 실험을 통해 검증했으며, 기존 연구들에서 많이 활용된 오토인코더와 비교하여 AUC, Accuracy, Precision, Recall, F1-score의 성능 평가를 진행한 결과 유니모달 오토인코더(UAE)와 멀티모달 오토인코더(Multimodal Autoencoder, MAE)의 성능을 상회하는 결과를 얻어 이상탐지에 있어 효과적이라는 것을 확인하였다.