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.

대장수술 후에 발생한 급성신부전의 위험인자

이혜미,황창재,김재황,김흥대,박대팔,서일숙,송선옥,김세연,이덕희,지대림 영남대학교 의과대학 2007 Yeungnam University Journal of Medicine Vol.24 No.2

연구 배경 : 급성 신부전은 술 후 발생할 수 있는 합병증 중에서 사망률은 큰 영향을 줄 수 있으므로 이 연구를 통해 위험인자를 알아보려고 한다. 재료 및 방법 : 2004년 1월부터 2006년 12월까지 3년간 영남대학교 의과대학 부속병원에서 대장 수술을 받은 570명의 환자들을 대상으로 하였다. 환자들의 성별과 연령, 미국 마취과학회 신체등급, 동반질환, 수술의 종류, 응급수술의 여부, 수술 시간, 재수술의 여부, 술 중의 투약 상황, 술 후에 자가 통증 조절기에 사용한 약제, 술 중에 저혈압의 유무, 수혈 여부, 술 후 기계적 환기를 시행한 경우를 비교하였다. 결과 : 비교 결과에서 성별과 수술의 종류, 응급 수술의 여부, 개복여부 등에는 유의한 차이를 보이지 않았다. 반면 환자의 나이와 수술 시간, 재수술의 여부, 술중에 이뇨제 등을 사용한 경우, 술 중에 저혈압의 유무, 술 후에 기계적 환기를 시행한 경우 등에는 유의한 차이를 보였다. 결론 : 이상의 결과로 급성신부전의 원인은 어느 한 가지라고 하기 보다는 위험인자에 얼마나 노출되어 있는가가 결정하는 것 같고, 그 원인들이 모여서 상승효과를 내는 것 같다. 그러므로 수술 전부터 많은 위험에 노출된 환자는 술 중 더 적극적인 감시를 시행하여 수술 후의 합병증 발생을 줄이는 노력을 기울여야 하겠다. Background : Acute renal failure is one of the leading causes of postoperative morbidity and mortality. The purpose of this study was to determine the risk factors that are associated with acute renal failure after colorectal surgery. Materials and Methods : Five hundred seventy patients who operated colorectal surgery at the Yeungnam University Medical Center over three years from 2004 to 2006 were enrolled in this study. The effects of gender, age, ASA classification, concomitant disease, surgery type and duration, reoperation, urogenital manipulation, medication, hypotension, hypovolemia, transfusion, and postoperative ventilatory care on the occurrence of acute renal failure after colorectal surgery were studied. Results : The major risk factors of acute renal failure after colorectal surgery were age of patients (P=0.003), ASA classification (P<0.001), concomitant disease (P<0.001), duration of the time surgery (P=0.034), reoperation (P=0.001), use of intraoperative diuretics (P=0.005), use of postoperative diuretics (P<0.001), intraoperative hypotension (P=0.018), intraoperative transfusion (P<0.001), postoperative transfusion (P<0.001), and postoperative ventilatory care (P=0.001). Conclusion : Multiple factors cause synergistic effects on the development of acute renal failure after colorectal surgery. Therefore, efforts to reduce the risk factors associated with acute renal failure are needed. In addition, intensive postoperative care should be provided to all patients.

보성산 유기농 녹차의 품질에 따른 카테킨 함량과 항산화능 비교 분석

박경련(Kyung Ryun Park),이상길(Sang Gil Lee),남태규(Tae Gyu Nam),김영준(Young Jun Kim),김영록(Young-Rok Kim),김대옥(Dae-Ok Kim) 한국식품과학회 2009 한국식품과학회지 Vol.41 No.1

유기농 녹차의 등급별 총페놀 함량과 항산화능은 각 추출 용매에 따른 수율을 확인하였을 때 물 추출에 비하여 수용성 유기용매의 추출 수율이 유의적으로 높았다. 유기용매를 이용한 추출수율은 물을 이용할 때 보다 총페놀 함량은 1.5에서 3.2배, 항산화능은 1.8에서 3.8배 정도 높게 나타났다. HPLC 분석을 통하여 총페놀 함량과 항산화능의 상관관계를 비교 시 총페놀 함량이 증가함에 따라 항산화능이 1차 선형관계로 증가하는 경향을 보였다. HPLC분석을 통하여 유기농 녹차에 함유되어 있는 다양한 카테킨의 함량이 채엽시기에 따라 변화가 나타났다. 유기농 녹차의 카테킨 성분 중 가장 많이 존재하는 EGCG가 건조중량당 5.8-7.7%의 함량을 보였고, caffeine은 1.7-2.9%의 함량을 보였다. 유기농 녹차의 카테킨 함량은 일반적으로 채엽 시기가 늦어짐에 따라서 점차 감소하였다. 유기농 녹차의 등급에 따른 항산화능은 최상급인 우전에서 가장 높았으며 최하등급인 엽차에서 가장 낮게 나타났다. HPLC 분석에 의한 유기농 녹차의 등급에 따른 총 카테킨 함량(㎎/g)은 우전(155.4), 세작(147.7), 중작(143.2), 엽차(135.1), 대작(130.5)의 순서로 감소하였다. 이를 통해 녹차의 채엽 시기가 유기농 녹차의 카테킨 성분 및 항산화능에도 영향을 미치는 것을 확인하였다. 전반적으로 상급의 유기농 녹차 일수록 총페놀 및 카테킨 함량이 많으며 또한 더 높은 항산화능을 가지는 것으로 나타났다. The objective of this study was to evaluate the effect of various solvents on extraction of bioactive phenolics and to analyze the antioxidant capacity and contents of individual catechins in various grades of green teas organically grown in Boseong, Korea. The organic green teas, based on their harvest seasons, were categorized into five grades such as Woo-Jeon, Se-Jak, Jung-Jak, Dae-Jak, and coarse tea. Solvents used to extract phenolics from these teas included water at 23℃ and 70℃ as well as 80% (v/v) aqueous methanol and ethanol. In general, aqueous organic solvents of methanol and ethanol led to higher extraction yields of phenolics than water at 23℃ and 70℃. Total phenolics and antioxidant capacity of the teas extracted with the aqueous organic solvents were approximately 1.5 to 3.2 and 1.8 to 3.8 times higher than those with water at 23℃ and 70℃, respectively. Coarse tea, the lowest grade of green tea, showed approximately 30-60% lower total phenolics and antioxidant capacity compared with the higher grade ones. Reversed-phase HPLC analysis was performed quantitatively to identify individual catechins, gallic acid, and caffeine in teas extracted with 80% (v/v) aqueous methanol. Based on their dry weights, the organic green teas contained about 1.7 to 2.9% of caffeine. Content (㎎/g dry weight) of tea catechins decreased in the following order: Woo-Jeon (155.4) > Se-Jak (147.7) > Jung-Jak (143.2) > coarse tea (135.1) > Dae-Jak (130.5). (-)-Epigall℃atechin gallate was the most abundant among the catechins analyzed. The highest grade of green tea, Woo-Jeon, had the highest amount of (-)-epigall℃atechin gallate at 77.4 ㎎/g dry weight. Overall, the higher grade of organic green teas tended to have the higher level of antioxidant capacity and catechins.

유효 음성 추출을 위한 머징알고리즘에 관한 연구

김진옥,황대준 成均館大學校 科學技術硏究所 2001 論文集 Vol.52 No.2

A valid speech-sound block can be classified to provide important information for speech recognition. The classification of the speech-sound block comes from the MRA(Multi-Resolution Analysis) property of the DWT(Discrete Wavelet Transform) which is used to reduce the computational time for the pre-procession of speech recognition. The merging algorithm is proposed to extract valid speech-sounds upon consideration of its position and frequency range. The merging algorithm needs some numerical methods for an adaptive DWT implementation and shows an unvoiced/voiced classification and a denoising. Since the merging algorithm can decide the processing parameters only at the standpoint of voices and is independent of system noises, it is more useful to extract valid speech-sounds. The merging algorithm has the adaptive feature for arbitrary system noises and an excellent denoising SNR (Signal-to-noise ratio).

멀티미디어 데이터 전송 시 강건한 오류 내성 기법을 적용한 오류 은닉

김진옥,황대준 成均館大學校 科學技術硏究所 2002 論文集 Vol.53 No.2

In network delivery of compressed video, packets may be lost if the channel is unreliable. Such losses tend to occur in burst. In this paper, a temporal and spatial error resilient video encoding approach is developed to facilitate the error concealment at the decoder against burst errors. Block interleaving scheme is introduced to isolate erroneous blocks caused by packet losses for spatial area of error concealment. Data hiding is applied to add protection parity bits for motion vectors between intra frames or continuous inter frames for temporal area of error concealment. Since bidirection interpolation for error concealment is adapted to error blocks at decoder, error occurred during the transmission are concealed fast and properly. In this study, data hiding is used to reduce a complexity of error concealment at the decoder. A set of feature are extracted at the encoder and embedded imperceptibly into the host media. If some part of the media data is damaged during transmission, the embedded features can be extracted and used for recovery of lost data. Experimental results suggest that our approach can achieve a reasonable quality for packet loss up to 30% over a wide range of video materials.

클러스터 인덱싱 구조 기반의 이미지 데이타 검색 연구

김진옥,황대준 成均館大學校 科學技術硏究所 2002 論文集 Vol.53 No.1

As the method of searching multimedia data, similarity retrieval has been studied to retrieve automatically basic features of multimedia data and to make search among data with retrieved features because exact match is not adaptable to matrix or vector format presentation of features of multimedia. In this study, we propose data clustering and indexing approach as speedy similarity retrieval method of multimedia data. This approach clusters similar images on adjacent disk cylinders and then builds indexes to access the clusters made. To minimize the search cost, the hashing is adapted to index cluster of this approach. In addition, to reduce I/O time, the proposed searching takes just one I/O to look up the location of the cluster containing similar object and one sequential file I/O to read in this cluster. The proposed schema that uses clustering making algorithm and hashing index simultaneously is shown higher search efficiency than VQ that uses just clustering.

복수 해상도 구순문 인식에 관한 연구

김진옥,황대준 成均館大學校 科學技術硏究所 2001 論文集 Vol.52 No.2

This paper presents a lip print recognition by pattern kernels for a person identification. A lip print recognition has been developed less than the other human physical attributes of a fingerprint, a voice pattern, a retinal blood/vessel pattern, or a facial recognition. The merit of a lip print recognition by CCTV camera is linked with other recognition systems such as retinal/iris eye and face. A new method with multi-resolution architecture is proposed to recognize a lip print by the pattern kernels. A set of the pattern kernels is a function of some local lip print pattern masks. This function converts the information on a lip print into the digital data. The recognition in the multi-resolution system is more reliable than recognition in the single resolution system. The results show that the proposed algorithm by the multi-resolution architecture can be efficiently realized.

항공기 사고, 생존 그리고 구조

김대중,박병옥 공군본부 의무감실 1992 항공의학 Vol.40 No.1-2

입시제도의 변화 : 누가 서울대학교에 들어오는가?

김광억,김대일,서이종,이창용 서울대학교 사회과학연구원 2003 한국사회과학 Vol.25 No.1-2

본 연구는 지난 30년간 서울대학교 사회과학대학 신입생들의 학생기록카드로부터 입학생의 출신지역, 부모학력 및 직업에 대한 Database를 구축하고, 이를 바탕으로 출신 지역별, 부모 학력 및 직업별 입학률 및 대학성적을 비교 분석하였다 본 자료의 구축과 연구는 그간 실증근거의 부족으로 인해 탁상공론에 그쳐왔던 교육성과 및 정책에 대한 논의에 대해 과학적 실증근거의 중요성을 강조하려는 목적으로 수행되었다. 본 연구에 의하면 부모 학력 및 직업에 따른 자녀의 입학률 격차가 확대되고 있으며 서울의 강남8학군 부유층 자녀의 입학률 프리미엄도 뚜렷하게 추정된다. 이는 그간 평준화 정책을 통해 교육기회의 평등을 추구하였음에도 불구하고 소득에 따른 자녀 입학률 격차가 확대되어 가고 있음을 시사한다 또한 이는 공교육 부실에 따라 사교육의 비중이 증가하고 있음을 반영하는 결과로서 이러한 문제를 개선하기 위해서는 평준화 정책의 수정 등 공교육 정상화를 위한 다방면의 노력이 요구되는 것으로 평가된다. This study analyses the admission rates and academic performance of the students in the Social Science Division of Seoul National University by their regional snd parental characteristics based on the database constructed from the past 30-year records of the students personal cards. Both the construction of the database and its analysis are motivated by the lack of the empirical evidence on educational performance in Korea, which has so far failed to lead various arguments on educational policies to any consensus. The results indicate that the differentials in admission rates by the parents'education and jobs have been widening and also that the admission rate has remained high among those residing in the relatively affluent Gangnam 8th school zone of Seoul. These imply that the differential by the parents'income has been widening despite the equalization policy in high school education that is supposed to have offered equal educational opportunities to the rich and the poor. The widening income-differential in admission rates appears to reflect that expensive private tutoring has become increasingly more important given the deterioration of public education. As a consequence, various efforts appear due, including the revision of the equalization policy, in order to substantially improve the performance of public education in Korea.

부산 ·경남지역 중학교 남학생의 학년에 따른 컴퓨터 음란물 접촉실태에 관한 연구

김혜옥,손혜숙,김대환,이종태 韓國保健敎育 ·健康增進學會 1999 보건교육건강증진학회지 Vol.16 No.2

To evaluate the status of the contact to lascivious computer programs and sexual attitude and behaviour by the grades of middle school boy students, the questionnaire survey was done on 715 students of five middle schools in Pusan and Kimhae area from December 15 to December 24, 1997. The data were analyzed by PC SAS; X² -test. The level of significance was 0.05. 404 students (56.5%) had a personal computer in their home. 516 students (72.2%) have experienced of using a computer program. 294(57%) of them usually played a game with computer. 514 students(71.9%) had experiences of the contact to a lascivious computer program, which increased with the grades of the students(p〈0.05). The first exposure to a lascivious program was when they were elementary school students in 24.6% of first grade middle school students, 13.8% of second grade, and 11.3% of 3rd grade students. 92% of the students was introduced to first contact through their friends. 63.7% of them watch the program at their friends home. The most common drives to contact to a lascivious programs were curiosity (53%). Sexual desire was a higher drive in third grade students (20.6%) than lower grades. After contacting to a computer lascivious program, desire of masterbation was more frequent in lower grade students, and feeling disgust was more frequent in higher grade students (p〈0.05). Frequence of masterbation or sexual intercourse was higher in high grade students(p〈0.05). In conclusion, distribution and popular use of computer attributes to the increased exposure to lascivious programs and lowering the age of first exposure. there was the difference according to the grades in the feeling and sexual behaviour after contacting to computer lascivious program. Appropriate methods to protect young students to contact a lascivious program should be sought. The use of computer should be educated in elementary school students accompanied by proper sex education.