신축학교 실내공기질이 초등학생들의 인지기능에 미치는 영향

김태섭,김선주,박시영,전만중,김규태,김창윤,정종학,백성옥,사공준 대한산업의학회 2007 대한직업환경의학회지 Vol.19 No.1

목적: 신축초등학교와 대조학교를 선정하여 교실 내 포름알데히드와 TVOCs를 측정하고 컴퓨터 신경행동검사를 이용하여 실내공기 오염물질이 학생들의 인지기능에 미치는 영향을 평가하였다. 방법: 신축초등학교 5학년 71명을 실내공기 오염물질 노출군으로 하고, 개교한지 12년째인 대구시의 일개 초등학교 5학년 2학급 63명을 대조군으로 하여 실내공기 오염물질농도 측정 및 컴퓨터 신경행동검사를 실시하였다. 결과: 신축학교에서 의도적으로 창문을 개방한 학급에서 1교시 포름알데히드 농도는 34.6 ㎍/㎥, 4교시에는 27.3 ㎍/㎥, 창문을 개방하지 않은 학급에서 1교시 80.2 ㎍/㎥, 4교시 127.1 ㎍/㎥, 대조학교에서는 2학급 각각 1교시에 12.6 ㎍/㎥, 7.5 ㎍/㎥, 4교시에 19.8 ㎍/㎥, 25.2 ㎍/㎥였다. TVOCs의 경우 신축학교의 의도적으로 창문을 개방한 학급에서 1교시에 농도는 487.2 ㎍/㎥, 4교시에 428.2 ㎍/㎥, 창문을 개방하지 않은 학급에서 1 교시에 농도는 1,283.5 ㎍/㎥, 4교시에 1,715.4 ㎍/㎥, 대조학교의 경우 2학급에서 각각 1교시에 농도는 240.9 ㎍/㎥, 150.8 ㎍/㎥, 4교시에 농도는 371.9 ㎍/㎥, 448.0 ㎍/㎥였다. 부호숫자 짝짓기의 평균반응시간은 대조학급이 1교시에 2,585 msec에서 4교시에 2,459 msec으로 감소한 반면 신축학교의 창문을 의도적으로 개방한 학급은 2,343 msec에서 2,510 msec으로, 평소대로 수업한 학급은 2,340 msec에서 2,563 msec으로 반응시간이 각각 167 msec, 223 msec 증가하였다. 1교시의 부호숫자 짝짓기 의 반응시간을 100%로 했을 때 창문을 의도적으로 개방 한 학급은 4교시에 5.9% 증가하였고(p<0.01), 평소대로 수업한 학급은8.3% 증가하였다(p<0.01). 반면에 대조학급은 4교시에 5.0% 감소하였다(p<0.01). 결론: 향후 학교의 실내공기질의 안전성 평가는 샘플링 된 공기의 오염수준의 측정뿐만 아니라 학생들의 건강영향도 함께 고려되는 것이 바람직할 것이다. Objectives: Most studies on the indoor air quality of newly built schools have focused only on the number of schools exceeding a standard or on subjective symptoms, such as sneezing, irritated eyes and an irritated nose. However, there has been no report on how poor indoor air quality affects children's academic performance. This study evaluated the effects of indoor air quality on the neurobehavioral performance of elementary school children. Methods: This study measured the indoor air pollutants and compared children's performance, using a computerized neurobehavioral test, between a newly built and a 12-year-old school. In addition, a questionnaire was administered regarding the indoor air quality related symptoms of children in a newly built and a 12-year-old school. Results: In the newly built school, the formaldehyde levels in the 1^(st) and 4^(th) classes with an open window were 34.6 and 27.3 μg/㎥, respectively. The levels in the 1^(st) and 4^(th) classes with the window closed were 80.2 and 127.1 μg/㎥, respectively. In the 12-year-old school, the formaldehyde levels in 1^(st) and 4^(th) class with open and closed window were 12.6 and 7.5 μg/㎥, and 19.8 and 25.2 μg/㎥, respectively. With respect to total volatile organic compounds, the levels in the 1^(st) and 4^(th) classes with the window open in the newly built school were 87.2 and 428.2 μg/㎥, respectively. In the 1^(st) and 4^(th) classes with the window closed, the total volatile organic compounds were 1,283.5 and 1,715.4 μg/㎥, respectively. In the 12-year-old school, the total volatile organic compounds were 240.9 and 150.8 μg/㎥, and 371.9 and 448.0 μg/㎥ in the 1^(st) and 4^(th) classes, respectively. In the case of a newly built school, the performance of the students in the neurobehavioral test in the 4^(th) class with the window closed was 8.3% lower than for those in the 1^(st) class with the window closed, but was only 5.9% lower when the windows were open. There was a statistical significant difference in the total numbers of symptoms between the two schools. Conclusions: These results suggest a proper evaluation of the indoor air quality within schools is required into both the level of contamination and the health effects of these contaminants toward children.

볼 베어링의 결함검출을 위한 Adaptive Line Enhancer의 적용

김영태,최만용,김기복,박해원,박정학,김종억,류준 한국공작기계학회 2005 한국생산제조학회지 Vol.14 No.2

The early detection of the bearing defects in rotating machinery is very important since the critical failure of bearing causes a machinery shutdown. However it is not easy to detect the vibration signal caused by the initial defects of bearing because of the high level of random noise. A signal processing technique, called the adaptive line enhancer(ALE) as one of adaptive filter, is used in this study. This technique is to eliminate random noise with little a prior knowledge of the noise and signal characteristics. Also we propose the optimal methods for selecting the three main ALE parameters such as correlation length, filter order and adaptation constant. Vibration signals for three abnormal bearings, including inner and outer raceways and ball defects, were acquired by Anderon(angular derivative of radius on) meter. The experimental results showed that ALE is very useful for detecting the bearing defective signals masked by random noise.

잡음환경에서 구름 볼 베이링의 결함검출을 위한 ALE의 적용

김영태,최만용,김기복,박해원,박정학,김종억,류준 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

It is very important to detect the bearing defects in rotating machinery since the critical failure of bearing cause a machinery shutdown. However it is difficult to detect the vibration signal resulting from the initial defects of bearing because of the high level of broadband noise. A signal processing technique, called the adaptive line enhancer(ALE) as one of adaptive filter, is studied in this work. This technique is to eliminate broadband noise without a prior knowledge of the noise and signal characteristics. Also we propose the optimal methods for selecting the three main ALE parameters such as correlation length, filter order and adaptation constant used in the adaptative process. Vibration signals for three abnormal bearings, including inner and outer raceways and ball defects, were acquired from Anderon(angular derivative of radius on)meter. The experimental results showed that the proposed technique can reliably detect the bearing defective signals masked by broadband noise.

慶南地域 中小企業 體質改善에 關한 硏究

金學壽,金容萬,尹泰烈,許南秀,元裕東 慶南大學校 産業經營硏究所 1988 産業經營 Vol.11 No.-

복합유기용제에 폭로된 근로자들에 대한 신경행동학적 기능의 평가

김창윤,전만중,정종학,성낙정,김상규,사공준,주 리 영남대학교 의과대학 1997 Yeungnam University Journal of Medicine Vol.14 No.2

복합유기용제를 취급하는 근로자들을 대상으로 유기용제의 폭로가 신경행동기능에 미치는 영향을 평가하기 위하여 대구지역의 중소규모 사업장에서 톨루엔, 크실렌, 메틸에틸케톤 및 신나에 만성적으로 폭로되는 유기용제 폭로군 48명과 폭로군과 같은 사업장에 근무하면서 유기용제에 폭로되지 않은 대조군 50명을 대상으로 1996년 8월에서 10월까지 연령, 교육수준, 음주, 흡연량 및 직업관련 변수들을 조사하고 Neurobehavioral Core Test Battery의 검사항목 중 Benton visual retention검사, 숫자부호 짝짓기, 숫자 외우기, 목적점찍기를 시행하였다. Benton visual retention검사는 폭로군이 7.9개, 대조군이 8.2개로 두군에서 유의한 차이가 없었으며, 숫자부호 짝짓기의 경우 폭로군이 55.6개, 대조군이 62.1개로서 폭로군이 유의하게 적었다(p<0.01). 숫자 외우기의 총 점수와 거꾸로 따라외우기의 점수가 폭로군에서 유의하게 적었으며(p<0.05, p<0.01) 목적점찍기의 바르게 찍은 점의 개수가 폭로군에서 유의하게 적었다(p<0.05).연령의 변화에 따른 신경행동기능의 일관성있는 변화는 없었으나 Benton visual retention검사의 경우 젊은 연령군이 고연령군에 비해 대조군에서 유의하게 높은 성적을 보였다(p<0.05). 부호숫자짝짓기의 경우 폭로군과 대조군 모두에서 학력이 높을수록 검사성적이 유의하게 높은 경향을 보였다(p<0.05). 숫자부호짝짓기에서 섭취하는 알콜의 량이 많을수록 폭로군의 부호숫자짝짓기 검사성적이 감소하는 경향을 보였다(p<0.05). 목적점찍기의 경우 폭로군에서 흡연량이 증가할수록 성적이 감소하는 경향을 보였다(p<0.05). 신경행동학적 검사성적을 종속변수로 하고 유기용제의 폭로유무, 나이, 학력수준, 알콜 및 흡연량을 독립변수로 한 다중회귀분석에서 Benton visual relention검사는 연령이 증가할수록 그 성적이 감소하는 경향을 보였으며(p<0.05), 숫자부호짝짓기는 학력이 높을수록 성적이 증가하는 것으로 나타났다(p<0.01). 숫자외우기에서는 유기용제의 폭로가 유의한 변수로 채택되었다(p<0.01). 목적점찍기의 총점수는 흡연량과 교육수준이(p<0.01), 바르게 찍은 개수는 흡연량과 유기용제의 폭로가 유의한 변수로 채택되었다(p<0.05). 유기용제의 폭로에 의해 지각반응(perception response)과 단기기억능력(short-term memory)이 민감하게 영향을 받는 것으로 평가되었으며, 특히 허용농도이하에서도 장기적으로 폭로되는 경우 폭로자의 신경행동기능에 변화를 초래할 수 있음을 확인할 수 있었다. NCTB에 의한 신경행동기능의 평가는 신경독성물질의 폭로이외에도 연령과 교육수준에 영향을 받으며 특히 지속적 운동능력의 경우 흡연에도 다소 영향을 받을 가능성을 제시하였다. A cross-sectional study was performed to evaluate the effects of chronic exposure to low-dose solvent on neurobehavioral performance of 48 male workers exposed to organic solvents. A control group of 50 workers was selected from same factories. Each worker completed a medical and occupational questionnaire and four tests of Neurobehavioral Core Test Bateery. These included Benton visual retention test, digit symbol, digit span,and pursuit aiming. Comparison of mean performance showed a significantly poorer performance on digit symbol, digit span, and pursuit aiming. In univariate analysis, age contributed to poor performance on Benton visual retention test and educational level was found to reduce the performance on symbol digit in both groups. Amount of alcohol intake was found to reduce the perfomance on digit symbol and smoking appeared to slow pursuit aiming in the exposure group. In multiple regression analysis, controlling for age, educational level, alcohol, and smoking, solvent exposure was found to be associated with performance of digit span, and number of correct dot of pursuit aiming. Age on Benton visual retention, educational level on digit symbol, and smoking on pursuit aiming were found to be a siginificant factors on each test items. This study suggest that short-term memory, and perception can be affected easily by chronic exposure of organic solvents which air concentration levels were under the Threshold Limit Value.

지역발전을 위한 LGIS사업의 집행전략 설계 및 집행전략

김학만 忠南大學校 地域開發硏究所 2004 地域開發論叢 Vol.16 No.-

종격동 종괴를 의심케한 우대동맥궁 1례

김만우,백학연,정춘해,장경식,홍순표,조건국,김종진 朝鮮大學校 附設 醫學硏究所 1987 The Medical Journal of Chosun University Vol.12 No.1

Developmental anomalies of the aortic arch, commonly known as vascular rings, are relatively rare congenital vascular anomalies which can compress the trachea and esophagus. One routine chest film of a patient who was checked and hepatoma-diagnosed in Internal Medicine, Chosun University Hospital left the room for doubt of mediastinal mass. But no subjective symptoms for the mass was told by the patient. This is to report our experience of a patient having right side aortic arch with aberrant left subclavian artery, as proved by diagnosis, but none of congenital heart disease. This right side aortic arch with aberrant left subclavian artery is the most frequent type among right aortic arch, the anomaly of which is usually detected from the incidental suspicion for mediastinal mass at routine chest film; because no symptoms are accompanied therewith.

大豆의 利用에 관한 硏究 : Ⅲ. 大豆PROTEIN-LIPID FILM의 性質에 관하여

金中晩,朴鶴封 圓光大學校 1981 論文集 Vol.15 No.1

대두protein-lipid film을 제조하여 그의 용해성(solubility), 팽윤성(swelliug power) 그리고 packaging properties을 조사하였는데 그 결과를 요약하면 다음과 같다 1. 대두protein-lipid film은 9.20%의 수분, 51.36%의 초단백질, 25.61%의 조지질, 9.57%의 total sugar 그리고 4%의 회분으로 구성되어 있다. 2. 대두protein-lipid film은 PH2-4에서 최저 팽윤도를 나타내 며 PH13~PHI4 사이에서 뚜렷한 용해 현상을 나타냈는데 이런 경향은 온도가 높아질 때 증대되었다. 3. 대두protein-lipid film은 김밥을 만들 때 김을 대체할 수 있으며 jelly, Sugar ball을 포장할 수 있는 가식성포장재로써의 적성을 가지고 있다. The property of soybean protein-lipid film was investigated and obtained following results; 1) Soybean protein-lipid film(dried at 50℃) contain moisture, crude protein, crude lipid total sugar and ash, 9.20%, 51.36%, 25.61%, 9.57%, 4%, respectively. 2) Soybean protein-lipid film showed maximum swelling rate in PH2-PH4, solubile in PH13-PH14 and according to temperature increase both were increased. 3) Soybean protein-lipid film have properties of packaging material of jelly, kim-bab and sugar ball.

W-CDMA 수신기 RF system 성능 분석 및 설계

김성호,지만구,김학선 한밭대학교 산업과학기술연구소 2001 논문집 Vol.5 No.-

In this paper, the RF system of the W-CDMA receiver is analyzed and designed. In order to obtain precise receiving performance parameter, we calculated each parameter which complied with specification(3GPP TS 34.121 V3.2.0). Noise Figure(NF) which is key parameter of receiver is derived from the specification. Linear characteristic and noise characteristic of the receiver system are analyzed by Phase Noise(PN) and Third Order Intercept Point(IP3) respectively. In addition, sweeping of the nonlinear component parameter which affects the linear performance is examined. Finally, we designed RF system which follows the available maximum parameters and introduced it in each part.

성인형 당뇨병 환자에서 피부생검을 이용한 표피하 모세혈관 기저막 두께의 변화에 관한 연구

김원학,오금탁,김만우,장경식,채종구,조건국 朝鮮大學校 附設 醫學硏究所 1987 The Medical Journal of Chosun University Vol.12 No.1

Thickening and proliferation of capillary basement membrane is a generalized phenomenon in diabetes mellitus and has been described in many organs including heart, kidney, pancreas, retina etc. While such changes are specific, it is difficult to obtain specimens from those organs. We took the specimens from the medial surface of the thing of 33 diabetics and 4 healthy persons as controls by means of punch biopsy. The measurement carried out by normogram and electron microscopic technique. HbA_(1c) values were also measured simultaneously. 1. The HbA_(1c) values are higher in diabetics than in control group (p<0.01). 2. The subepidermal capillary basement membrane thickness of the diabetics : 30% of the 5 th decade population, 53.9% of the 6 rh decade population and 83.3% of the 7th decade population showed more rhan 3,000 A. Whereas all the controls showed below 3,000 A. 3. The subepidermal capillary basement membrane thickness did nor increase significantly with the duration of the disease. 4. In cases of high subepidermal capillary basement membrane thickness, HbA_(1c) showed significant increase. (p<0.01).