• 제목/요약/키워드: Arithmetic average

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Design of an Efficient Bit-Parallel Multiplier using Trinomials (삼항 다항식을 이용한 효율적인 비트-병렬 구조의 곱셈기)

  • 정석원;이선옥;김창한
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.13 no.5
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    • pp.179-187
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    • 2003
  • Recently efficient implementation of finite field operation has received a lot of attention. Among the GF($2^m$) arithmetic operations, multiplication process is the most basic and a critical operation that determines speed-up hardware. We propose a hardware architecture using Mastrovito method to reduce processing time. Existing Mastrovito multipliers using the special generating trinomial p($\chi$)=$x^m$+$x^n$+1 require $m^2$-1 XOR gates and $m^2$ AND gates. The proposed multiplier needs $m^2$ AND gates and $m^2$+($n^2$-3n)/2 XOR gates that depend on the intermediate term xn. Time complexity of existing multipliers is $T_A$+( (m-2)/(m-n) +1+ log$_2$(m) ) $T_X$ and that of proposed method is $T_X$+(1+ log$_2$(m-1)+ n/2 ) )$T_X$. The proposed architecture is efficient for the extension degree m suggested as standards: SEC2, ANSI X9.63. In average, XOR space complexity is increased to 1.18% but time complexity is reduced 9.036%.

The Most Efficient Extension Field For XTR (XTR을 가장 효율적으로 구성하는 확장체)

  • 한동국;장상운;윤기순;장남수;박영호;김창한
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.12 no.6
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    • pp.17-28
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    • 2002
  • XTR is a new method to represent elements of a subgroup of a multiplicative group of a finite field GF( $p^{6m}$) and it can be generalized to the field GF( $p^{6m}$)$^{[6,9]}$ This paper progress optimal extention fields for XTR among Galois fields GF ( $p^{6m}$) which can be aplied to XTR. In order to select such fields, we introduce a new notion of Generalized Opitimal Extention Fields(GOEFs) and suggest a condition of prime p, a defining polynomial of GF( $p^{2m}$) and a fast method of multiplication in GF( $p^{2m}$) to achieve fast finite field arithmetic in GF( $p^{2m}$). From our implementation results, GF( $p^{36}$ )longrightarrowGF( $p^{12}$ ) is the most efficient extension fields for XTR and computing Tr( $g^{n}$ ) given Tr(g) in GF( $p^{12}$ ) is on average more than twice faster than that of the XTR system on Pentium III/700MHz which has 32-bit architecture.$^{[6,10]/ [6,10]/6,10]}$

Exposure Assessment of Dust, Ultra Fine Dust(Particulate Matter 2.5, PM2.5) and Black Carbon among Aircraft Cabin Cleaners (항공기 기내 청소노동자의 분진, 초미세먼지(PM2.5) 및 블랙카본 노출수준 평가)

  • Hyunhee Park;Sedong Kim;Sungho Kim;Seung-Hyun Park
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.33 no.2
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    • pp.171-187
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    • 2023
  • Objectives: Aircraft cabin cleaning work is characterized by being performed within a limited time in a narrow and enclosed space. The objective of this study was to evaluate the exposure levels to dust, ultra fine dust(PM2.5) and black carbon(BC) among aircraft cabin cleaners. Methods: Active personal air sampling for respirable dust(n=73) and BC(n=47) was conducted during quick transit cleaning(cabin general and vacuum-specific) and seat cover replacement and total dust and PM2.5 were area-air-sampled as well. Also, size distribution of particle was identified with the cleaning workers targeted. Dusts were collected with PVC filters using gravimetric analysis. The concentration of PM2.5 and the particle size distribution were measured with real-time direct reading portable equipment using light scattering analysis. The concentration of BC was measured by aethalometer(filter-based real-time light absorption analysis instrument). Results: The geometric mean of respirable dust was the highest at vacuum cleaning as 74.4 ㎍/m3, following by replacing seat covers as 49.3 ㎍/m3 and cabin general cleaning as 47.8 ㎍/m3 . The arithmetic mean of PM2.5 was 4.83 ~ 9.89 ㎍/m3 inside the cabin, and 28.5~44.5 ㎍/m3 outside the cabin(from bus and outdoor waiting space). From size distribution, PM2.5/PM10 ratio was 0.54 at quick transit cleaning and 0.41 at replacing seat covers. The average concentration of BC was 2~7 ㎍/m3, showing a high correlation with the PM2.5 concentration. Conclusions: The hazards concentration levels of aircraft cabin cleaners were very similar to those of roadside outdoor workers. As the main source of pollution is estimated to be diesel vehicles operating at airports, and it is necessary to replace older vehicles, strengthen pollutant emission control regulations, and introduce electric vehicles. In addition, it is necessary to provide as part of airport-inftastructure a stable standby waiting space for aircraft cabin cleaners and introduce a systematic safety and health management system for all workers in the aviation industry.

Public Exposure to Natural Radiation and the Associated Increased Risk of Lung Cancer in the Betare-Oya Gold Mining Areas, Eastern Cameroon

  • Joseph Emmanuel Ndjana Nkoulou II;Louis Ngoa Engola;Guy Blanchard Dallou;Saidou;Daniel Bongue;Masahiro Hosoda;Moise Godefroy Kwato Njock;Shinji Tokonami
    • Journal of Radiation Protection and Research
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    • v.48 no.2
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    • pp.59-67
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    • 2023
  • Background: This study aims to reevaluate natural radiation exposure, following up on our previous study conducted in 2019, and to assess the associated risk of lung cancer to the public residing in the gold mining areas of Betare-Oya, east Cameroon, and its vicinity. Materials and Methods: Gamma-ray spectra collected using a 7.62 cm×7.62 cm in NaI(Tl) scintillation spectrometer during a car-borne survey, in situ measurements and laboratory measurements performed in previous studies were used to determine the outdoor absorbed dose rate in air to evaluate the annual external dose inhaled by the public. For determining internal exposure, radon gas concentrations were measured and used to estimate the inhalation dose while considering the inhalation of radon and its decay products. Results and Discussion: The mean value of the laboratory-measured outdoor gamma dose rate was 47 nGy/hr, which agrees with our previous results (44 nGy/hr) recorded through direct measurements (in situ and car-borne survey). The resulting annual external dose (0.29±0.09 mSv/yr) obtained is similar to that of the previous study (0.33±0.03 mSv/yr). The total inhalation dose resulting from radon isotopes and their decay products ranged between 1.96 and 9.63 mSv/yr with an arithmetic mean of 3.95±1.65 mSv/yr. The resulting excess lung cancer risk was estimated; it ranged from 62 to 216 excess deaths per million persons per year (MPY), 81 to 243 excess deaths per MPY, or 135 excess deaths per MPY, based on whether risk factors reported by the U.S. Environmental Protection Agency, United Nations Scientific Committee on the effects of Atomic Radiation, or International Commission on Radiological Protection were used, respectively. These values are more than double the world average values reported by the same agencies. Conclusion: There is an elevated level of risk of lung cancer from indoor radon in locations close to the Betare-Oya gold mining region in east Cameroon. Therefore, educating the public on the harmful effects of radon exposure and considering some remedial actions for protection against radon and its progenies is necessary.

Effect of Taeeumjoweetang on the Body Composition, Serum Lipid Level and Antioxidant Enzyme Activity of Obese Female College Students (태음조위탕의 적용이 태음인 비만여대생의 신체조성, 혈청지질농도 및 혈중 항산화 효소에 미치는 효과)

  • Kim, Hye-Ju;Ahn, Hong-Seok;Oh, Eun-Ha;Kim, Young-Locke
    • Journal of Sasang Constitutional Medicine
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    • v.23 no.3
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    • pp.391-401
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    • 2011
  • 1. Objectives: Though the eating habits have improved and the living method has become convenient according to the economic growth thanks to the modern industrialization, because of the lack of exercise, obesity, wrong eating habits and stress etc, various symptoms of disease of adults are on the rise. This is the phenomenon that happens as the eating life has become life in the West along with the inundation of the western culture in our society. In this perspective, there has been many various clinical research that's been proceeded so far about the physical constitution and obesity, but there has been little research on the objective analysis of the clinical research about the alimentotherapy using taeeumjoweetang. 2. Methods: In this research we have checked the weights, fat rates, fat weight, abdominal fat rate, blood pressure, and BMI over the objects of the women that were diagnosed as lunisolar system as their physical constitution, and assessed the paramecium lipid, in-blood antioxidation enzyme and the damage of oxidization in the urine by physical constitution-specific of the body shapes that were determined by BMI. The statistical analysis of the current research was processed by using of SPSS 17.0 program. We have figure out statistical amounts such as the arithmetic average, average deviation rate and percentage number. Fro the verification of he significancy of each elements, we have used the paired t-test, ANOVA, Chi-square test at the level of p<0.05. 3. Results and Conclusions: Their characteristics are age $21.20{\pm}1.35$, height $160.30{\pm}6.11cm$, weight $64.66{\pm}8.72kg$, fat rates are $35.97{\pm}4.87%$, fat amount $23.40{\pm}5.48$, abdominal fat rate $0.823{\pm}0.03$, BMI $25.12{\pm}2.79kg/m^2$, and systolic blood pressure $111.60{\pm}10.28mmHg$ and diastolic blood pressure $68.60{\pm}7.43mmHg$ and we have let them take the medicine twice a day for 8 weeks. The clinical result for the Cholesterol, Triglyceride, HDL-cholesterol, LDL-cholesterol, SGOT, SGPT, of the object people was that for the function of the liver, the result of the SGOT and SGPT test was $17.16{\pm}3.05$, $15.00{\pm}2.99IU/L$, which was a decrease, and had statistical meaning, but for the SGOT, though the figure reduced to $11.92{\pm}4.61$, $10.80{\pm}3.07$, it had no statistical meaning. For the whole cholesterol level, the figure reduced to $169.00{\pm}19.95$, $160.08{\pm}22.52$ mg/dL and had statistical significance(p<0.05). Neuter fat number, Triglyceride has slightly increased to $67.52{\pm}36.32$, $68.08{\pm}47.33$ mg/dL but did not have any statistical meaning. The antioxdant enzyme marker standard marker, SOD has increased to $2.52{\pm}0.73$, $2.86{\pm}0.60U/ml$, and had statistical significance(p<0.01). Catalase also increased by $0.63{\pm}0.18$, $1.07{\pm}0.25mmol/ml$ and had statistical meaning(p<0.01). GPx also increased to $204.76{\pm}32.64$ nmol/ml and had statistical meaning(p<0.01). But, for the Total antioxidant, though it has raised to $1.51{\pm}0.26$, $1.57{\pm}0.17nmol/{\mu}l$, it did not have any statistical meaning. MDA of oxidative stress marker has decreased to $1.70{\pm}0.68{\mu}g/ml$, $1.21{\pm}0.50{\mu}g/m$ and had statistical significance(p<0.01). 8-OHdG also decreased $3.35{\pm}0.95ng/ml$, $2.21{\pm}0.50ng/ml$ and had statistical meaning(p<0.01). In this research, we have analyzed the various markers relating to BFM and changes in oxidative enzyme in blood by takingtaeeumjoweetang. Taeeumjoweetang has the positive effect on inbody antioxidant system and reducing the content of cholesterol, which is proven to help losing weight and improving hyperlipidemia statistically. With this research, we hope to improve the lifestyle of those who are either obese or need to manage their dietary habits, and also to become the touchstone of integrating Oriental Medicine with the science of food & nutrition.

A Study on the Status of Management and Intake of Fats & Oils (유지류의 관리와 섭취실태에 관한 연구)

  • 김인숙;안명수
    • Korean journal of food and cookery science
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    • v.4 no.1
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    • pp.75-85
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    • 1988
  • This survey was conducted to investigate about purchasing, use and management of cooking oil, and the intake amounts of each food and fats & oils from each food on 296 housewives in a big city, medium and small city, farming village, fishing village, and mountain village from June 5 to July 20 in 1987. The percentage and $x^2$-test were used in data analysis and the arithmetic mean of the gross intake divided by the total subjects gave the intake amounts per capita per day. The results of this study are as following; 1. Purchasing and keeping of cooking oil. The reading ratio of label in purchasing cooking oil was high among housewives of cities and highly educated housewives. There were dissatisfactions about quality (46.7%), price (33.7%), and packing (19.5%) after purchasing cooking oil. Cooking oil was being kept mainly in glasses (64.7%) or in synthetic plastics (31.5%), and also in dark & cool places. 2. Use and refining of cooking oil. More housewives (70.6%) kept cooking oil used once in a different container after filtering. The housewives re-using used oil after adding new oil to it were only 30.0%. There were a lot of housewives frying foods twice or three times in the same oil. 3. Intake of fats & oils and foods containing fats & oils. Average intake amounts of food containing fats & oils per person per day was 6.85g in fats & oils, 42.96g in meat & its products, 95.13g in fishes & shellfishes, 22.89g in eggs, 60.69g in legumes & its products, 61.00g in milk & milk products, 4.22g in seeds & nuts, and 9.36g in instant noodles. Average intake amounts of fats & oils per person per day taken from these foods was 6.4g from fats & oils, 2.3g from meat & its products, 4.3g from fishes & shellfishes, 2.7g from eggs, 3.0g from legumes & its products, 2.5g from milk & milk products, 1.8g from seeds & nuts, and 1.7g from instant noodles.

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An Analytical Study of the Quality of Life in Dental Hygienists in Seoul (서울지역 치과위생사의 삶의질(Quality of Life)에 관한 분석 연구)

  • Kim, Yeun-Sun
    • Journal of dental hygiene science
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    • v.5 no.1
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    • pp.39-43
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    • 2005
  • This study was carried out to provide fundamental data for an examination of a health promotion program by determining the influence of the Health Promoting Lifestyle Profile on the quality of life of female dental hygienists. The sample was selected from the population of 1,148 who were registered in the Association of Seoul Dental Hygienists. 800 subjects were randomly selected from 25 districts in Seoul. The data was collected by calling the dental hygienists to, explaining the contents and objective of our study, and sending them a questionnaire by post. The questionnaire consists of the total number of 97 questions: 62 questions on the Health Promoting Lifestyle Profile, 26 questions on the quality of life and 9 general characteristics questions. The data was collected from August 16 to October 15, 2004. Out of 800 subjects, 481(60.1%) completed the questionnaires. For statistical analysis, the frequency, percentage, arithmetic mean, ANOVA, and multiple regression analysis, were analyzed using the SAS 8.1 Analysis program. The significance level was set to 0.05. The results of this study were as follows: First, The average score of the subjects' quality of life was 3.1. For the sub-categories, it was shown that the degree of satisfaction on the condition of society was the highest at 3.2, and the degree of satisfaction on the condition of the individuals was the lowest at 3.1. The average score of the Health Promoting Lifestyle Profile variable was 2.5. For the sub-categories, it was shown that the degree of sanitary life was at 3.2, and degree of the professional health maintenance was the lowest at 1.7. Second, There were significant differences in the Quality of Life benefits of action with the general characteristics. There were significant differences in age, educational level, income, marital status, career, and Perceived Health Status. There were significant difference in Health Promoting Lifestyle Profile benefits of action with the general characteristics. There were significant differences in terms of age, educational level, income, marital status, career, and the Perceived Health Status. Finally, The stepwise multiple regression analysis revealed that the powerful predictors were Health Promoting Lifestyle Profile, income and the Perceived Health Status. These factors accounted for 37.6% of the variance in the Quality of Life patterns. As the subjects were limited to dental hygienists in Seoul, care should be taken when applying these results to all dental hygienists in Korea. In order to generalize the study, a large number of subjects selected from all regions in Korea will be needed.

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The Effect of Rain on Traffic Flows in Urban Freeway Basic Segments (기상조건에 따른 도시고속도로 교통류변화 분석)

  • 최정순;손봉수;최재성
    • Journal of Korean Society of Transportation
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    • v.17 no.1
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    • pp.29-39
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    • 1999
  • An earlier study of the effect of rain found that the capacity of freeway systems was reduced, but did not address the effects of rain on the nature of traffic flows. Indeed, the substantial variation due to the intensity of adverse weather conditions is entirely rational so that its effects must be considered in freeway facility design. However, all of the data in Highway Capacity Manual(HCM) have come from ideal conditions. The primary objective of this study is to investigate the effect of rain on urban freeway traffic flows in Seoul. To do so, the relations between three key traffic variables(flow rates, speed, occupancy), their threshold values between congested and uncontested traffic flow regimes, and speed distribution were investigated. The traffic data from Olympic Expressway in Seoul were obtained from Imagine Detection System (Autoscope) with 30 seconds and 1 minute time periods. The slope of the regression line relating flow to occupancy in the uncongested regime decreases when it is raining. In essence, this result indicates that the average service flow rate (it may be interpreted as a capacity of freeway) is reduced as weather conditions deteriorate. The reduction is in the range between 10 and 20%, which agrees with the range proposed by 1994 US HCM. It is noteworthy that the service flow rates of inner lanes are relatively higher than those of other lanes. The average speed is also reduced in rainy day, but the flow-speed relationship and the threshold values of speed and occupancy (these are called critical speed and critical occupancy) are not very sensitive to the weather conditions.

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An Investigation on the self-consciousness Symptoms of the Clerical Workers attendant upon Office Automation (사무 자동화에 따른 사무직 근로자의 건강과 연관된 자각 증상에 대한 조사연구)

  • Jung, Mi Wha
    • Korean Journal of Occupational Health Nursing
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    • v.3
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    • pp.54-70
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    • 1993
  • According as the automation of clerical work(OA ; Office Automation) develops, the use of VDT(Visual or Video Display Terminal) is increasing suddenly. But, in proportion to the spread of office automation(OA tendency), the self-conciousness syptom attendant upon the work is appearing also (Kim, Jung Tae, Lee, Young Ook, 1990). The apparatuses of office enable the clerical workers to be convenient and perform mass businesses. But, they are increasing the opportunity to be exposed to VDT syndrom, techno stress, computer terminal disease, pain by muscle strain(RSI), bradycausia of noise nature, and electromagnetic waves, etc. which are referred to as the new type of occupational diseases to the workers. It is the real situation that the workers to use VDT is complaining of the physical inconvenience sense in the recent newspaper and literature, it is the point of time that the sydrome to come from VDT use and computer terminal disease, etc. must be classified into the occupational disease(Lee, Kwang Young 1990, Lee, Kyoo Hak 1990, Lee, Won Ho 1991, Lee, Si Young 1991, Lee, Joon 1991, Choi, Young Tae 1991, Heo, Seung Ho 1989). In addition, it is the real situation that the scientifitic study result about the scope that electromagnetic waves has influence on the human body has not been suggested yet, and criticism on the stable exposure permission standard about electromagnetic waves to be emitted from VDT and on the problem in the health about electromagnetic waves is continuing. (IEEE Spectrum, 1990). In addition according to the experience of nursery business of industry field, it is the real situation that the patients who consult complaining of physical and mental inconvenience sence, among the users of apparatus of office automation, are reaching 10% of the patients coming to doctor's room. Therefore, it is necessary to confirm the self-consciousness symptom that the clerical workers complain of multilaterally with the actual state examination about the use of the apparatuses of offices automaton. Thus, this study was tried as th basic data for the cosultation and education for the maintenance and furtherance of the health of workers as the nurse of industry field, by confirming the contents of self-consciousness symptom attendant upon the use of the apparatus for office outomation making the financial institution in which the spparatus for office automation in most frequently used as the subject, and by examining whether there is the difference according to the subject of study, the data were collected, by using the questionnaire method, making 200 workers who consented to the study participation as the subject, among the persons who have spent over 3 months since they used the apparatuses for office automation and didn't receive the treatment in hospital due to the clerical disease for recent 3 years. The period of data collection was from Oct. 9, 1991 to Oct. 12. As for the measurement instrument about the complaint if self-consciousness symptom attendant upon the use of apparatuses fo office automation, the question item on the complaint symptom of health problem attendant upon the treatment of VDT that Kim(1991) developed and on CMI health problem and the question items on the fatigue degree due to industry were used by previous examination to 25 persons. Collected data were analyzed with the statistical method such as percentage, arithmetic mean, Person correlation coeffient, Kai square verfication, t-test, ANOVA, etc. by using SPSS/PC+ program, and the result is as follows : 1. The self-consciousness symptom that the clerical workers complained of most frequetly appeared high in 'My eyes are tired'(99.4%), 'I feel fatigue and weariness'(99.4%), 'I feel that my head is heavy5(90.0%), 'eyesight fell'(88.8%), 'I have a stiff neck'(88.8%), 'I fell pain in the shoulder'(85.0%), 'I feel cold and painful in the eyes'(76.9%), 'I feel the dry sense of eyeball'(76.2%), 'My nerves are edgy, and I an fretful, (75.6%), 'I feel pain in the waist'(73.2%) and 'I fell pain in the back'(72.8%). It emerged that the subject use the apparatuses for office automation complained of self-consciousness symptoms related to visual symptoms and musculoskeletal symptoms. 2. As for the general feature of examination subjects, the result to see the distribution by classifying into sex, age, school career, use career of apparatuses for office automation, skillfulness degree of the use of apparatus for office automation, use hours of the apparatuses for office automation per 1 day, type of business of the apparatus for office automation, rest hours during the use of apparatus for office automation, satifaction degree of business of office automation, and work circumstance, etc. emerged as follows : As for the sex of subjects, the distribution showed that men were 58.8% and women were 41.3%, Age was average 26.9. As the distribution of school career, the distribution showed that4below the graduation of high school' was 58.8%, 'graduation from junior college-university' was 35.0%, and 'over graduate school' was 6.3%. In the question to ask the existence or non-existence of experience of health consultation in connection with the work of office automation, the response that I had the consultation exprience and I feel the necessity emergerd as 90.1% And, the case that the subject who didn't wear the glasses or lens before using the OA apparatus wear glasses or lens after using OA apparatus emerged as 28.3% of whole. As for the existence or non-existence of use career of OA apparatus, the case under 3 years was highest as 52. 7%. As for the skillfulnness degree about the use of apparatus for office automation, most of them are skillful with the fact that 'common' was 44.4%, 'skill' was 42.5%, and 'unskillful' was 13.1% As for the use average hours of the apparatus for office automation per 1 day, the distribution showed that the case under 3-6 hours was 33.1%, the case under 6-9 hours was 28.1%, the case under 3 hours was 30.6%, and the case over 9 hours was 8.1% Main OA business and the use hours for 1 day showed in the order of keeping and retrieval, business of information transmission(162min), business of information transmission(79.3 min), business of document framing(55.5 min), and business of duplication and printing(25.4min). as for the rest during the use of apparatus for affice automation, that I take rest occasion demands the major portion, but that I take after completing the work emerged as 33.8%. Though the subiness gets to be convenient by the use of the apparatus for of office automation, respondents who showed the dissatisfaction about the present OA business emergd high as 78.1%. The work circumstances of each office was good with the fact that the temperature of office was 21.8, noise was average 42.7db, and the illumination was average 364.4 lx, in the light of ANSi/HFS 100 Standard. 3. Sight syptom, musculoskeletal symptom, skin and other symptoms showed the significant difference according to the extent of skillfulness of the apparatus for office automation. All the symptoms exept skin symptom showed the difference according to the use hours of the apparatus for office automation. All the question items exept the sytoms of digestive organs and the rest hours during the apparatus for office automation showed the signicant difference. The question item which showed the signicant difference from the satisfaction degree of present OA business showed the significant difference from all the question item classified into 6 groups. But, age and school career didn't significant difference from the complaint of any self-consciousness symptoms.

    . In conclusion, the self-consciousness symptoms of the subjects to use OA apparatus appeared differently, according to sex distiction, skillfull degree of OA apparatus, use hours of OA apparatus, the rest hours during th use of OA apparatus, and the satiafaction degree of persent business. Therefore, it is necessary that the nurse in the inuctry field must recognize to receive the education about the human technological physical condition which is most proper for te use of OA apparatus and about the proper rest method until they get accustomed to the use of OA apparatus. In addition, the simple exercise relax the tention of muscle due to the repetitive simple movement, and the education for the protection of eyesight are necessary.

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  • Human Risk Assessment of Polybrominated Diphenyl Ethers by Breast Milk Feeding of Infants (영유아의 모유 섭취에 따른 폴리브롬화디페닐에테르의 위해성 평가)

    • We, Sung-Ug;Cho, Bong-Hui;Cho, Yu-Jin;Yoon, Cho-Hee;Choi, Shi-Nai;Min, Byung-Yun
      • Journal of Korean Society of Environmental Engineers
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      • v.34 no.2
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      • pp.109-118
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      • 2012
    • This study achieves results from 22 maternity breast milk samples in total to demonstrate exposure level and risk assessment of PBDEs in Seoul area. PBDEs were detected in all the breast milk samples of the present study, indicating that general population in these Seoul area are widely exposed to these chemicals. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged of 0.84~13.1 ng/g lipid with an arithmetic mean and median of 3.56 ng/g lipid and 2.6 ng/g lipid, respectively. Global comparison shows that the levels of total PBDEs were relatively similar to those of China, Taiwan and European country (Sweden), and somewhat higher than those in some Asian (Vietnam, Philippines, and Indonesia). In the present study, however, the levels of total PBDEs in human milk are still one to two orders of magnitude lower than those in North America. Contribution rate of each congener appeared to be predominant with BDE-47, followed by BDE-153, BDE-100, BDE-99, BDE-154 and BDE-183. The sum of BDE-47 and BDE-153 accounted for more than 65% of total PBDEs in most samples. From the result of the human risk assessment of infants for total PBDEs and BDE-47 by breast milk feeding, we could find out that the average daily doses and hazard index (95th percentile) were 16.5 ng/kg bw/day and $1.2{\times}10^{-1}$ each other when nursing for 6 months after infants born. However, it was concluded that the infant health hardly had adverse seriously effects under this research condition.


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