• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5A
• /
• pp.407-415
• /
• 2010

In Korea, more than 90% of the total number of steel bridges built for 40~70 m span length is a steel box-girder bridge type. A steel box-girder bridge is suitable for long span or curved bridges with outstanding flexural and torsional rigidity as well as good constructability and safety. However, a steel box-girder bridge is uneconomical, requiring many secondary members and workmanship such as stiffeners and ribs requiring welding attachments to flanges or webs. Therefore, in US and Japan, a plate girder bridge, which is relatively cheap and easy to construct is generally used. One type of the plate girder bridge is the two- or three-main girder plate bridge, which is a composite plate girder bridge that minimizes the number of required main girders by increasing the distance between the adjacent girders. Also, for the simplification of girder section, the stiffener which requires attachment to the web is not required. The two-main steel girder plate bridge is a representative type of plate girder bridges, which is suitable for bridges with 10 m effective width and has been developed in the early 1960s in France. To ensure greater safety of two- or three-main girder plate bridges, a larger steel section is used in the bridge domestically than in Europe or Japan. Also, the total number of two- or three-main girder plate bridge constructed in Korea is significantly less than the steel box girder bridge due to a lack of designers' familiarity with more complex design detailing of the bridge compare to that of a steel box girder bridge design. In this study, a new construction method called Turn Over method is proposed to minimize the steel section size used in a two- or three-main girder plate bridge by applying prestressing force to the member using confining concrete section's weight to reduce construction cost. Also, a full scale 20 m Turn Over girder specimen and a Turn Over girder bridge specimen were tested to evaluate constructability and structural safety of the members constructed using Turn Over process.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5A
• /
• pp.557-564
• /
• 2009

In recent years, there have been numerous explosion-related accidents due to military and terrorist activities. Such incidents caused not only damages to structures but also human casualties, especially in urban areas. To protect structures and save human lives against explosion accidents, better understanding of the explosion effect on structures is needed. In an explosion, the blast overpressure is applied to concrete structures as an impulsive load of extremely short duration with very high pressure and heat. Generally, concrete is known to have a relatively high blast resistance compared to other construction materials. However, information and test results related to the blast experiment of internal and external have been limited due to military and national security reasons. Therefore, in this paper, to evaluate blast effect on reinforced have concrete structure and its protective performance, blast tests are carried out with $1.0m{\times}1.0m{\times}150mm$ reinforce concrete slab structure at the Agency for Defence Development. The standoff blast distance is 1.5 m and the preliminary tests consists with TNT 9 lbs and TNT 35 lbs and the main tests used ANFO 35 lbs. It is the first ever blast experiment for nonmilitary purposes domestically. In this paper, based on the basic experiment procedure and measurement details for acquiring structural behavior data, the blast experimental measurement system and procedure are established details. The procedure of blast experiments are based on the established measurement system which consists of sensor, signal conditioner, DAQ system, software. It can be used as basic research references for related research areas, which include protective design and effective behavior measurements of structure under blast loading.

• 한국노년학
• /
• v.29 no.1
• /
• pp.329-352
• /
• 2009

This study examined life in old age and images of the aged perceived by middle-aged and old-aged generations through indepth interviews with 30 persons aged 40s through 80s residing in three areas (city or county) in capital region in Korea to use it as basic information in planning social welfare policy and reorganizing social services in response to population aging in capital region in Korea. In terms of economic life of the middle-aged and olde-aged generations perceived older people's opportunities for work were rarely given to the aged due to ageism and negative stereotypes of aging and the aged, and the aged tended to regard themselves less able or unable to work. In terms of social life of the aged both middle-aged and old-aged generations perceived that the frequency of social participation was low, and the daily life of the aged was found mostly aimless, unorganized and unplanned. In terms of psycho-social life of the aged both generations still felt that they were not alienated from the family, neighbors, and the society. In terms of social welfare services both generations thought the aged needed basic services such as income maintenance, health care, housing services, and particularly they felt lack of social services. The old-aged generation was willing to travel to the distance taking more than one hour to receive social services that they would need. Both the middle-aged and the old-aged agreed upon the necessity of preparation for old age and the benefits of earlier preparation, however, they said that they could not prepare for their old age due to lack of social programs to help preparation for old age and due to spending for rearing and education of their children. In terms of perceived life in old age both middle-aged and old-aged generations tended to be slightly positive, but the degree of positiveness differed between respondents from urban area and those from rural area regardless of generations. Images of the aged were perceived to be overwhelmingly negative while positive images were very few in number regardless of generations. This finding may suggests that negative stereotypes on aging and the aged are also prevalent in Korean society like in Western societies. Based on findings of this study some implications for social policies in response to population aging in capital region were suggested.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.2
• /
• pp.145-154
• /
• 2019

The purpose of this study is to investigate the performance, learning motivation and satisfaction of the students who take the university 's Lifelong Education Program. The research method was interviewed. The results are as follows. In terms of operations; First, the awareness of the kindness of employees of the college lifelong education institute needs to be strengthened at the beginning of the school year. Second, in the operation of the College Lifelong Education Center, the support such as the parking fee should be extended to the students. Third, lifelong education facilities should be supplemented. In terms of participation motivation; First, it can be seen that there are the most learners who want to do complementary learning. Most of them are people who look back on their lives and prepare for their future directions. Second, as the life span of human beings became longer, the economic preparation for life became necessary. Thus, all learning tends to be perceived as a preparation for economic income. Third, most people who participate in lifelong education are very interested in health. Therefore, it is necessary to increase the motivation for participation by expanding health related programs. In terms of satisfaction; First, it depends on the purpose of the individual. Satisfaction was high for those who aimed at hobbies and relationships, and satisfaction for those who aimed for economic activities was low. Second, it is also necessary to consider the instructor 's instructional process. In other words, lifelong learners tend to be adults, so little complaints are not revealed. Therefore, I would like to ask the lecturers to advance the education for the class. The implications for the improvement direction of the lifelong education center are as follows; First, we need to drastically reduce the number of programs overlapping with other universities and conduct research to develop new programs. In order to do this, it is necessary to continuously carry out a survey of demanders' needs. Second, it is necessary to find the appropriate place for program operation considering the movement distance of learners. It should be avoided that the program should be operated with the existing university facilities. Third, universities' lifelong education should go to education that includes college students.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.3
• /
• pp.181-192
• /
• 2019

The purpose of this study is to look at the fun that high school students from blind schools feel in sports programs. A questionnaire was used to collect data from 10 out of 12 blind schools nationwide, including 122 male and 102 female students. Research tools are open questionnaires and questions are as follows. - Questionnaire: "Write down three of the most interesting things about sports programs." The data analysis was done with frequency analysis and the following conclusions were drawn. First, male high school students at blind schools are able to build up their physical strength in the area of competent factors (control-self) (23, 21.5%), in the area of competent factors (7, 77.8%) and in the area of motion-related factors (competition) (24, 15.1%), and in the area of non-execution factors (26, 37.7%), Second, high school girls with visual impairments did not respond in the areas of proficiency (control-self) because of stress release (25, 26.6%), in the areas of control-tain), in the areas of movement (competition) because they were able to do various exercises (22, 15.7%), and in the areas of non-watering (environmental) (18, 37.5%). Third, in the sports program comparative analysis of high school students between genders of blind schools, boys are interested in health and physical fitness in the field of competent factors (control-self) and girls are considered to be a means of relieving stress. In the field of competent factors (control-others), boys and girls can react to a variety of sports opportunities. In the future, by studying the fun of students in the physical education program through research to find out more fun in the school physical education program, we will explore practical ways to maximize student participation and increase motivation level The educational aspect of the process, that is, the educational value provided by the physical education, should be composed of content that can change the thinking and behavior of the teacher and the student so that the program contents and operation method.

• (The) Research of the performance art and culture
• /
• no.39
• /
• pp.279-323
• /
• 2019

The musical characteristics of Fishing songs in North Korean which recorded on Anthology of North Korean Folk Songs were examined in this paper. The results are as follows. Among Fishing songs in North Korea, there are "Rowing Song," the "Song for Hauling Nets," and the "Song for Picking Up Fish" in songs related to walleye pollack fishing and in songs related to croaker fishing, the "Song for Dropping Anchor" and the "Full-Load-of-Fish Song" in songs related to croaker fishing, the "Song for Weighing Anchor," the "Song for Shaking Fish," the "Full-Load-of-Fish Rowing Song," and the "Song for Hanging Walleye Pollack" in songs related to walleye pollack fishing. There are the "Song for Setting a sail" and the "Song for catching shells" in Fishing songs in North Korea, too. In the rhythmic elements of Fishing songs in North Korea, the tempo of the "Songs for Setting a sail" is moderato, and that of the "Songs for Picking Up Fish" of songs related to anchovy or herring fishing is quite slow. "Rowing Songs"(croaker fishing) have various tempos but faster than moderato, and usually get faster and faster as time goes by. Most songs have 4/♩. time and there are some of 2, 3 or 5 time. Some songs use irregular time or 6 time overlapping 2 beats. The mode Menari is the most common tonal system used in fishing songs of North Korea. And the mode Susimga, the mode Changbutaryeong, the mode Nanbongga, and the mode Odolttogi are also used in the tonal system of Fishing songs in North Korea. There are shoutting intonations that have indefinite pitch, too. Modulation or interaction by the mode Changbutaryeong appeared in songs of the mode Menari. There is a tendency to favor a certain tonal system by category. Responsorial form is mostly used, but in the most cases, they were sung in solo. In responsorial songs, several calling songs overlap with the responding songs. Durchkomponiert form is sung by antiphon or in solo, but the case sung in solo originally seems to have been sung by antiphon or unison, if we consider the procedure of the work. The "Song for Picking Up Fish" of Seonbong-gun of North Hamgyeong Province and Yangyang-gun of Gangwon Province, the "Full-Load-of-Fish Song-Bongjuktaryeong" of Jeungsan-gun of South Pyeongan Province and "Full-Load-of-Fish Song-Baechigisory" of Taean-gun of South Chungcheong Province, "Rowing Song" of Nampo City and Ganghwa-gun of Gyeonggi Province are resembled. In neighboring areas, even if the songs of different categorys, sometimes share a same melody. In a certain category, sometimes a same melody is shared to a considerable distance. It was first identified that in anchovy or herring fishing or dybowskii' sand eel fishing, the "Song for Picking Up Fish" is widely shared in the East Sea Coast area.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_1
• /
• pp.589-597
• /
• 2023

Floating debris in large quantities from land during heavy rainfall has adverse social, economic, and environmental impacts, but the monitoring system for the concentration area and amount is insufficient. In this study, we proposed an efficient monitoring method for floating debris entering the river during heavy rainfall in Daecheong Lake, the largest water supply source in the central region, and applied remote sensing techniques to estimate the standing-stock of floating debris. To investigate the status of floating debris in the upper of Daecheong Lake, we used a tracking buoy equipped with a low-orbit satellite communication terminal to identify the movement route and behavior characteristics, and used a drone to estimate the potential concentration area and standing-stock of floating debris. The location tracking buoys moved rapidly during the period when the cumulative rainfall for 3 days increased by more than 200 to 300 mm. In the case of Hotan Bridge, which showed the longest distance, it moved about 72.8 km for one day, and the maximum moving speed at this time was 5.71 km/h. As a result of calculating the standing-stock of floating debris using a drone after heavy rainfall, it was found to be 658.8 to 9,165.4 tons, with the largest amount occurring in the Seokhori area. In this study, we were able to identify the main concentrations of floating debris by using location-tracking buoys and drones. It is believed that remote sensing-based monitoring methods, which are more mobile and quicker than traditional monitoring methods, can contribute to reducing the cost of collecting and processing large amounts of floating debris that flows in during heavy rain periods in the future.

• Journal of the Korean Society of Radiology
• /
• v.17 no.6
• /
• pp.851-857
• /
• 2023

The purpose of this study is to investigate the effect of changes in collimation size and sub ROI on exposure index(EI) in hand radiography, present collimation size and EI suitable for average hand size of Koreans, and present the effect of changes in sub ROI on EI. The subjects of this study were hand-wrist phantom, and the exposure conditions were set to 55 kVp, 125, mA, and 6.25 mAs, and source to image receptor distance was applied to 110 cm. Based on the vendor recommended sub-ROI (18.7" × 18.7", 8" × 10", 8" × 7.4", 6" × 7.4")and the textbook's recommended sub-ROI 8" × 10", each obtaining 30 images, and comparing the EI shown in the equipment. The EI according to the change in the size of the collimation were 1663.7±4.52, 8"×10" is 1489.1±4.49, 8"×7.4" is 1716.9±3.00, 6"×7.4" is 168.7±3.66 for each EI, and the average value of each value was statistically significant. The average EI according to the sub ROI change was 1489.1±4.49 for SS, LS was 1694.8±5.19 for AEC, 2052.9±5.96, VR was 1548.3±3.20, and HR was 1663.2±4.33. The appropriate field size considering the hand size of Koreans was found to be 8"×7.4". In addition, when the field size increases based on the generally known field size (8"×10") during hand radiography, the EI value changes from a maximum of 15% to a minimum of 11%, and the sub ROI shape based on sub ROI 'SS' Depending on the change, the EI value increased from a maximum of 37% to a minimum of 3%.

• Journal of the Korean Society of Radiology
• /
• v.17 no.6
• /
• pp.903-909
• /
• 2023

The purpose of this study is to compare and analyze the effect of changes in the patient's central position on the exposure dose and image quality of surrounding organs during a chest lateral examination using an Auto Exposure Control(AEC). The experiment was conducted on a human body phantom. A needle was attached to the lower part of the center of the coronal plane of the phantom, and a lead ruler was attached to the lower part of the detector so that the 50 cm point was located at the lower center of the AEC ion chamber. The exposure conditions were 125 kVp, 320 mA, the distance between the source and the image receptor was 180 cm, and the exposure field size was 14 × 17 inches. Only one AEC ion chamber was used at the bottom center, and the density was set to '0' and sensitivity to 'Middle', and the central X-ray was incident vertically toward the 6th thoracic vertebra. With AEC mode applied, the 50 cm point of the needle and lead ruler were aligned and the phantom was moved 5 cm toward the stomach (F5) and 5 cm toward the back (B5), and the dose factor was analyzed by measuring ESD. The ESD of the thyroid gland according to the change in patient center position was 232.60±2.20 μGy for Center, 231.22±1.53 μGy for F5, and 184.37±1.19 μGy for B5, and the ESD of the breast was 288.54±3.03 μGy for Center, F5 was 260.97±1.93 μGy, B5 was 229.80±1.62 μGy, and the ESD of the center of the lung was 337.02±3.25 μGy for Center, F5 was 336.09±2.29 μGy, and B5 was 261.76±1.68 μGy. As a result of comparing the average values of dose factors between each group, the difference in average values was statistically significant (p<0.01), and each group appeared to be independent. As a result of the study, there was no significant difference in the dose to the thyroid, breast, and center of the lung according to the change in the patient's central position, except for the breast (10%) when the patient moved forward about 5 cm. However, movement of about 5 cm posteriorly resulted in an average dose reduction of 23.7%. Additionally, when the patient's central position was moved to the rear, image quality deteriorated.

• Korean Journal of Remote Sensing
• /
• v.39 no.6_2
• /
• pp.1615-1633
• /
• 2023

Sargassum horneri is one of the floating algae in the sea, which breeds in large quantities in the Yellow Sea and East China Sea and then flows into the coast of Republic of Korea, causing various problems such as destroying the environment and damaging fish farms. In order to effectively prevent damage and preserve the coastal environment, the development of Sargassum horneri detection algorithms using satellite-based remote sensing technology has been actively developed. However, incorrect detection information causes an increase in the moving distance of ships collecting Sargassum horneri and confusion in the response of related local governments or institutions,so it is very important to minimize false detections when producing Sargassum horneri spatial information. This study applied technology to automatically remove false detection results using the GOCI-II-based Sargassum horneri detection algorithm of the National Ocean Satellite Center (NOSC) of the Korea Hydrographic and Oceanography Agency (KHOA). Based on the results of analyzing the causes of major false detection results, it includes a process of removing linear and sporadic false detections and green algae that occurs in large quantities along the coast of China in spring and summer by considering them as false detections. The technology to automatically remove false detection was applied to the dates when Sargassum horneri occurred from February 24 to June 25, 2022. Visual assessment results were generated using mid-resolution satellite images, qualitative and quantitative evaluations were performed. Linear false detection results were completely removed, and most of the sporadic and green algae false detection results that affected the distribution were removed. Even after the automatic false detection removal process, it was possible to confirm the distribution area of Sargassum horneri compared to the visual assessment results, and the accuracy and precision calculated using the binary classification model averaged 97.73% and 95.4%, respectively. Recall value was very low at 29.03%, which is presumed to be due to the effect of Sargassum horneri movement due to the observation time discrepancy between GOCI-II and mid-resolution satellite images, differences in spatial resolution, location deviation by orthocorrection, and cloud masking. The results of this study's removal of false detections of Sargassum horneri can determine the spatial distribution status in near real-time, but there are limitations in accurately estimating biomass. Therefore, continuous research on upgrading the Sargassum horneri monitoring system must be conducted to use it as data for establishing future Sargassum horneri response plans.