• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.67-74
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• 2019

In this paper the response factor is investigated for middle and small size-RC slab aged bridges. The response factor consists of static and dynamic response factors and is a main parameter in the frequency based-bridge load carrying capacity prediction model. Static and dynamic response factors are determined based on the frequency variation and the impact factor variation respectively between current and previous (or design) states of bridges. Here, the impact factor variation is figured out using the impact factor response spectrum which provides the impact factor according to the natural frequency of bridges. In this study, four actual RC slab bridges aged over 30 years after construction are considered and their span length is 12m. The dynamic loading test in field using a dump truck and eigenvalue analysis with FE models are conducted to identify the current and previous (or design) state-natural frequencies of the bridges, respectively. For more realistic considerations in the moving loading situation, the impact factor response spectrum is developed based on tri-axle moving loads representing the dump truck load distribution and various supporting conditions such as simply supported and both ends fixed conditions. From the results, the response factor is widely ranged from 0.21to 0.91, showing that the static response factor contributes significantly on the results while the dynamic response factor has a small effect on the result. Compared to the results obtained from the impact factor response spectrum based on the single axle-simply supported condition, the maximum percentage difference of the response factors is below 3.2% only.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.93-113
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• 2019

The behavior of the 3 hinged precast arch structure was investigated by comparing field measurements with numerical analyses performed for precast lining arch structures, which are widely used for the open-cut tunnel. According to the field measurements, the maximum vertical displacement occurred at the crown with upward displacements during the backfilling up to the crown of the arch and downward displacements at the backfill height above the crown. The final crown displacement was 19 mm upward from the original position. The horizontal displacement at the sidewall, which had a maximum horizontal displacement, occurred inward of the arch when compacting the backfill up to the crown and returned to the original position after completing the backfill construction. According to the analysis of displacement measurements, economical design is expected to be possible for precast arch structures compared to rigid concrete structures due to ground-structure interactions. Duncan model gave good results for the estimation of displacements and deformed shape of the tunnel according to the numerical analyses comparing with field measurements. The earth pressure coefficients calculated from the numerical analyses were 0.4 and 0.7 for the left and the right side of the tunnel respectively, which are agreed well with the eccentric load acting on the tunnel due to topographical condition and actual field measurements.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.18-30
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• 2021

The ultimate goal of the present study is to establish the acoustical performance standards of classroom for the elderly who are incomplete hearing people. As a pilot survey, the present study was conducted to investigate the listening environment and the actual condition of speech perception performance of education facilities for elderly, Acoustic performances of two education facilities for elderly in Cheongju were measured and questionnaire survey was done to elderly people. Also, speech intelligibility tests were undertaken by Consonant Vowel Consonant (CVC) and Phonetically Balanced Words (PBW) methods. The questionnaire survey showed that the elderly were satisfied with the listening environment of the educational facilities in general. Also, it was found that acoustical performances satisfy with the acoustic criteria of general classrooms in Korea. However, the results of the speech intelligibility test showed that the scores of elderly were significantly lower than twenties with normal hearing. It was also revealed that the scores are reduced as the age increases. Thus, it was concluded that the acoustical performance standards of educational facilities for the normal hearing were not suitable for educational facilities for the elderly.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.32 no.1
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• pp.171-197
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• 2021

The purpose of this study is to suggest the ways of improving systematic records management based on the results of analyzing the present records management situation of college and department in an university which is operating archives. To achieve the purpose, survey and interview of the persons in charge of producing and managing the administrative documents of college and department were conducted. Furthermore, actual condition investigation of records management of college and department and university archives were analyzed. According to the results of analysis, the following problems were found: 1) lack of sufficient records management by college and department, 2) lack of understanding of tasks by processing staffs, 3) operational problems of university archives. Based on the results, recommendations were made as follows; First, it is necessary to improve an awareness of records management by operating staffs. Second, it is necessary to educate staffs through the development of training programs reflecting the characteristics of the university and set up guidelines for records management by college and department. Third, it is necessary to execute reorganization and supplement the personnel of university archives.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.119-135
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• 2022

This paper used dynamic centrifuge tests to examine the seismic response for a deep temporary retaining wall with four input motions of 100, 1,000, and 2,400 years of return periods. The centrifuge model was designed based on an actual deep excavation design with a 50 m maximum excavation depth. The model backfill was prepared with dry silica sand at a relative density of 55%, and the retaining wall was modeled as a 24.8 m height diaphragm wall supported by struts. Acceleration response was amplified at the backfill surface, top of the wall, and near bedrock. However, in the middle of the model, input motion was de-amplified. The member forces of the wall and strut induced by the seismic load, which excited, were compared with the member force at rest condition. The wall's maximum negative and positive moments were increased to 36% and 10% compared to the maximum moment at rest. The maximum axial force increases to 70% of the at rest axial force on the bottom strut. The equivalent static analysis using Mononobe-Okabe (M-O) and Seed-Whitman (S-W) seismic earth pressures were compared to the centrifuge results. Considering the bending moment, the analysis results with the M-O theory underestimates but that with the S-W theory overestimates.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.62-67
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• 2023

Due to the prolonged impact of COVID-19, the demand for Information Technology (IT) products is increasing, and their production facilities are expanded. Consequently, the use of harmful and dangerous chemicals are increased, the risk of fire(s) and explosion(s) is also elevated. In order to mitigate these risks, the government sets standards, such as KS C IEC 60079-10-1, and manages explosion-prone hazardous facilities where flammable substances are manufactured, used, and handled. However, using the standards of KS, it is difficult to predict the actual possibility of an explosion in a facility, because ventilation (an important factor) is not considered when setting up a hazardous work environment. In this study, the SEMI S6, Tracer Gas Test was applied to the chemical vapor deposition (CVD) facility, a major part of the display industry, to evaluate ventilation performance and to confirm the possibility of creating a less explosive environment. Based on the results, it was confirmed that the ventilation performance in the assumed scenarios met the standards stipulated in SEMI S6, along with supporting the possibility of creating a less explosive working condition. Therefore, it is recommended to use the prediction tool using engineering techniques, as well as KS standards, in such hazardous environments to prevent accidents and/or reduce economic burden following accidents.

• The Journal of Korean Society for School & Community Health Education
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• v.5
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• pp.85-105
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• 2004

The purpose of this study is to provide basic data for practical and concrete program development, which can give students satisfaction in sex education. To achieve this purpose, an actual status of sex education for high school student and their sexual experience were investigated. And then tried to find out if there is difference of satisfaction in sex education and contents that they want to learn based on having sexual experience or not. For this study, a questionnaire of sexual awareness was conducted on 562 students among first graders and second graders of high school located in Kongju city, from on October 4th, 2004 to on October 15th. But only 550 answer sheets among 562 were analyzed, for 12 answer sheets were not proper enough to apply to this study. The collected data was computerized using SPSS WIN in frequency and percentage for actual condition of sex education and sexual experience and for satisfaction at the result of sex education based on having sexual experience or not. And then the $x^2$-test was verify the difference. The requirement for sex education, based on having sexual experience or not, was analyzed using t-test by computerizing the average and standard deviation. The conclusion of this study are as followings; 1. 93.8% students have ever been taught for sex education by teachers, but nursing teacher among them was the higher percentage than any other teachers. They took courses for sex education in discretion class, and the teaching method was a kind of lecture. 2. After taking sex education, 37.6% students said that it was boring, for they had already known the contents of the courses, and 43.8% students said that they acquired sex knowledge through the Internet and mass media. 3. It was highest percentage that 36.9% students had no agony about sex. The most serious worry was a sexual impulse and the sexual psychology of the opposite sex. To solve these worries, 61.6% students said that they consulted with their friends. 4. It showed that 89.9% male students and 71.6% female students had experiences various lascivious materials, 81.4% male students, 7.2 female students experienced masturbation, 52.7% female student and 44.8% male students experienced kissing or hugging, and 13.7% male students and 9.9% female students experienced sexual intercourse. 5. The satisfaction for sex education based on having sexual experience or not was different. In short, it showed that the students who experienced sexual experiences such as accessing to lascivious materials, kissing, hugging, and sexual intercourse except masturbation thought that sex education was important than the students who didn't experience sexual experiences. On the other hand, the students who didn't experience sexual experiences were more satisfied with the contents and level of sex education than the students who experienced sexual experiences. 6. The requirement for sex education based on having sexual experience or not was also different. The students who experienced sexual experiences wanted to learn an acquaintance with the other sex than the others. On the other hand, the students who didn't experience sexual experience wanted to learn friendship and love. The students who experienced sexual experience except masturbation was more desirable for taking sex education than the other students. In conclusion, it is fully required that sex education should be regular subject in school and teachers who are charge of sex education should be experts in this field, for only expert can teach systematic and adequate sex knowledge to students. In addition, it is also essential to understand contents of sex education which can be satisfactory for students' requirement. So we should develop concrete and practical programs for sex education.

• Journal of Environmental Health Sciences
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• v.40 no.6
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• pp.454-468
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• 2014

Objectives: This study was conducted to investigate the actual condition of the farm work environment and personal protective equipment as part of the effort to improve livestock work for the safety and health of poultry farmers and provide basic data for establishing plans to improve and develop personal protective equipment. Methods: For this purpose, a questionnaire survey on general information about stables, the poultry work environment, accidents, the wearing of work clothes and personal protective equipment, and the level of awareness related to personal protective equipment was conducted among 148 poultry farmers. Results: As a result, it was found that poultry workplace environment was exposed to such risks as fine dusts; organic dusts; poisonous gases; odorous substances; chicken excrement; contact with chickens, bacteria or viruses; and accidents related to machine operation. Thirteen percent of respondents suffered severe respiratory diseases, and the most frequently injured sites due to accidents were the hands (25.7%), knees (23.8%), arms (17.3%), and head (10.9%). The most frequent type of accident was collisions between the body and obstacles or machinery during movement (36.4%), followed by erroneous machine operation such as feeders and electric shocks (8.5%). Regarding the wearing of work clothes and personal protective equipment, 51.7% of the respondents wore worn-out clothing or everyday clothes, whereas only 32.0% wore work clothes. The percentage of farmers who wore proper protective equipment for the work environment during poultry work was 48.4%. The most frequently used type of protective equipment was boots (38.9%), followed by mask (36.7%), gloves (36.3%), appropriate work clothes (22.6%), quarantine clothes (17.6%), helmets (13.4%), and goggles (12.6%). The rate of wearing goggles was low because they were considered inconvenient and lowered work efficiency. Furthermore, they purchased everyday products available on the market for their personal protective equipment which were not appropriate for maintaining safety in an actual harmful environment and its consequent risks. As a result of the survey of the awareness level related to personal protective equipment, their levels of awareness of accidents and attitude proved to be average or higher, but the practice of wearing protective equipment and the level of knowledge and management of personal protective equipment were lower. Conclusion: This survey found that the wearing status of personal protective equipment among poultry farmers was insufficient even though they were exposed to risks. Most respondents were aware of the necessity of wearing personal protective equipment and of the potential for accidents, but they did not wear proper protective equipment. Their wearing rate was low due to a lack of knowledge about protective equipment, as well as the inconvenience of wearing it. Therefore there is a need to improve and develop specialized personal protective equipment for respiration, hands, and eyes, as well as work clothes that can protect farmers from major harmful matter that is generated in the poultry workplace. Based on the results of this investigation, we will conduct further studies on the required performance and design directions of personal protective equipment while collecting more objective data through field-oriented assessments.

• Korean Security Journal
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• no.2
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• pp.259-289
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• 1999

The Security Industry has dynamic working conditions. So this study intends to find the advisable direction for the reduction of accidents. To achieve the aim, the investigation of documents and the examinations of actual proofs have been done to figure the theoretical background and to see the basic knowledge of security industry. The questionnaire was composed of two question sheets to search real data and actual proofs, with making targets of pure security organization and personnel. The one consists of 9 questions to find the scale and extent of security organizations and the population and character of security personnel, and the other 25 questions in 3 major areas to analyze the causes, the frequency rates, the factors, and the condition of accidents. The period of survey was July 15th to October 15th in 1997 by mail/telephone/interview. The questionnaires were efficiently returned from 102 different organizations including the public security groups of Seoul Metropolitan Police Bureau and so on, with the information of 8,222 persons having worked for Korean Security Industry in 1996. So being based on the reality, some meaningful facts were found, and were compared with the national statistics of the Government. This study is made up of 5 chapters : in the 1st chapter the motivation, the object, the method, the direction and the limitation of the approach were presented ,in the 2nd chapter the theoretical background were inferred ; in the 3rd chapter the collected data of accidents in Korean Security Industry were analyzed and explained on the base of the questionnaires , in the 4th chapter the advisable facts connected with preventing accidents were mentioned ; in the last the conclusion were stated. With the replies of 102 different organizations including the information of 8,222 persons in 1996, the main facts found or analyzed through this study are as follows. Firstly, accident is an unpredictable and occasional event. It occurs to man and/or thing, but the frequency rate of accidents in Korean Government and other Institutes has been calculated and evaluated only in the point of the accident related with man. Secondly, the factors of accidents are firstly relevant to the way preventing accidents in Security Industry in Korea. However the frequency rate is academically calculated and evaluated by at once man(population) and hour(time). But the Government has done the rate only by man(population). This can be improper and inaccurate rates. Thirdly, the confused concept of security is used in Korean Government, academic society, corporation and so on. Therefore the detailed formation of the concept is needed for the development of Security Industry in Korea. Fourthly, security organizations can be classified into 'public security(public law enforcement)' and 'private security' according to its identification, and furthermore 'private security' can be divided into 'facilities-guard service', 'body-guard service', and 'patrol service' according to its major role. Fifthly, in the viewpoint of the number of both organization and population,'facilities-guard service' is centered in Korean 'private security'. According to the analyzed results of the questionnaires in this study, the frequency rate of accidents of Korean Security Industry is 0.43(%) totally in 1996 : 'facilities-guard service' 0.54(%), 'body-guard service' 0.12(%), and 'patrol service' 0.21(%) in 'private security', and 'public security' 0.20(%). With regard to the accident frequency rate of organization and population, 'facilities-guard service' is the highest. The accident frequency rate of population in 'facilities-guard service' organization ranges dispersively from 0.20(%) to 11.11(%). Sixthly, the accidented rate of workers having serviced for under one year is 57.6(%). This can mean that the main factor of accidents in Korean Security Industry is the lack of role-understanding and training/education. And another factor can be found on the time of accident occurrence. Many accidents have been occurred on the relaxed points like as just after lunch and morning rush-hour. Lastly, the major advisable facts related to preventing accidents are as follows : The workers who are over fifty years old in 'facilities-guard service' organization need to be educated for preventing accidents ; It is desirable that the training and education to prevent accidents should be practiced in the time of pre-service ; As the style of accidents and the age of the accidented are not same according to major service area('public security' and 'private security' : 'facilities-guard service', 'body-guard service', and 'patrol service'), the plans to prevent accidents must be different and various. However fracture and bruise are general accidents in Korean Security Industry ; Workers must care about traffic accident and violent fall ; It seems that the grouped working with other two persons will reduce accident occurrence possibility rather than individually single working.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.741-757
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• 2012

This study had targeted the Seunghwanglim of Wonju in order to understand the forest vegetation's present condition. And then we compared the change in vegetation of Seunghwanglim for 24years. It was intended to provide basic data for conservation and management. Actual vegetation as a result of investigation, a total area of $56,231m^2$ Quercus serrata forest(7.02%), Acer triflorum forest(5.71%), and Deciduous Broad-Leaved Forest and Pinus densiflora forest(6.4%) were distributed variously. Present condition of the plains forest has 34 kinds of canopy species, 65 kinds of understory species, 70 species of shrubs species, 88 species of total species. And the plains forest has 500 individuals of canopy layer, 1,102 individuals of understory layer. Mean importance percentage of the major species showed Ulmus davidiana var. japonica(15.6%), Acer triflorum(15.2%), Pinus densiflora(11.1%), Quercus serrata(9.8%). Acer triflorum diameter at Ulmus davidiana var. japonica were a relatively wide range. Results of change for 24 years, vegetation of Seunghwanglim was changed from Quercus serrata-Acer triflorum to Ulmus davidiana var. japonica-Acer triflorum. Big trees over than DBH 30cm were surveyed total 18 species, 166 individuals. Increased over than the past 63 individuals. Seunghwanglim was destroyed by reckless past. Since 1990, the outer perimeter fence was installed to control human access. After that, understory layer and shrub layer were developed. And big tree was increased. Which is considered to restore damaged ecosystems. In order to conservation and protection of Seunghwanglim, people have to management and monitor about exotic species such as Robinia pseudo-acacia, Populus tomentiglandulosa, Castanea crenata, Pueraria lobata, etc.