• Education of Primary School Mathematics
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• v.22 no.1
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• pp.13-27
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• 2019

The use of grid paper in elementary mathematics textbooks is used in numbers and calculations, figures and measurement areas. Among them, it is used most in the figure area. In spite of this utilization, it is necessary to supplement it because it is difficult to revise or supplement the trial and error that often occurs in the course of the course, as the process of using the textbook paper in the actual class. The use of grid paper in elementary mathematics textbooks is used in numbers and calculations, figures and measurement areas. Among them, it is used most in the figure area. In spite of this utilization, it is necessary to supplement it because it is difficult to revise or supplement the trial and error that often occurs in the course of the course, as the process of using the textbook paper in the actual class. In this study, we tried to find out the usability of grid paper boards which can be used more effectively than the grid paper among the teaching aids presented in the 'Development of teaching aids standards for math class' of Korea Foundation for the Advancement of Science & Creativity(2017). A questionnaire survey was conducted on the use of grid paper and grid paper board for teachers who actually use grid paper in elementary mathematics. As a result, we found out the achievement criteria of grid paper board utilization and investigated the study subject which is effective to use grid paper board. In particular, we have identified specific learning topics that are effective in each area and presented specific activities.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.963-968
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• 1990

An iterative learning control scheme for tracking control of a class of uncertain nonlinear systems is presented. By introducing a model reference adaptive controller in the learning control structure, it is possible to achieve zero tracking of unknown system even when the upperbound of uncertainty in system dynamics is not known apriori. The adaptive controller pull the state of the system to the state of reference model via control gain adaptation at each iteration, while the learning controller attracts the model state to the desired one by synthesizing a suitable control input along with iteration numbers. In the controller role transition from the adaptive to the learning controller takes place in gradually as learning proceeds. Another feature of this control scheme is that robustness to bounded input disturbances is guaranteed by the linear controller in the feedback loop of the learning control scheme. In addition, since the proposed controller does not require any knowledge of the dynamic parameters of the system, it is flexible under uncertain environments. With these facts, computational easiness makes the learning scheme more feasible. Computer simulation results for the dynamic control of a two-axis robot manipulator shows a good performance of the scheme in relatively high speed operation of trajectory tracking.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.165-172
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• 2014

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N1 class species. $N_1O_1$, $N_1O_2$, and $N_2$ class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

• Journal of Species Research
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• v.12 no.3
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• pp.212-223
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• 2023

A total of 30 bacterial strains were identified in the classes Betaproteobacteria and Gammaproteobacteria in the study of prokaryotic species in Korea. These strains were isolated from a variety of environmental sources, including soil, tidal flat, mud, wetland, pine cone, seaweed, sea sediment, and brackish water. Phylogenetic analysis showed that isolates were identified based on high 16S rRNA gene sequence similarities (≥98.7%) with the predefined bacterial type species. In this study, we present data on previously unreported species from Korea, including 10 species from three families of one order in the class Betaproteobacteria and 20 species from 12 families of nine order in the class Gammaproteobacteria. Morphological, biochemical characteristics, isolation sources, and NIBR deposit numbers are provided in the description sections.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.179-187
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• 2020

This paper investigates the construction equipment accidents by time. Construction sites are unique with many different hazardous conditions which cause accidents. According to the Occupational Safety and Health Administration (OSHA), accidents related to construction equipment are one of the most leading causes of fatal injuries in the construction industry. While there have been many studies investigating the equipment-related accidents, few research studies provided in-depth analyses about the time that accidents frequently occurred. By using the OSHA accidents data collected between 1997 and 2012, this paper analyzed the accidents data by time, equipment type including excavator, backhoe, dozer, and crane, accident cause, and injury class. The analyses revealed that the time window with most accidents was between 13:00 and 13:59. In terms of the injury class, the time windows with the highest numbers of equipment accidents were between 13:00 and 13:59 and between 11:00 and 11:59 for fatality and hospitalization, respectively. For the accident causes, equipment operator's error was the highest number of accident causes. It is expected that findings from the analyses can be used to more strategically develop management plans and guidelines to prevent accidents related to construction equipment to practitioners.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.3
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• pp.274-294
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• 2007

The most reasonable method of counting the number of the estuaries in Korea may be counting the number of streams flowing into the sea. The number counting of the streams should be carried out based on the river classes (National River, Regional 1st Class River and Regional 2nd Class River) given by the River Act. The National River scale estuaries are totaled to thirteen, i.e. Han River(including Imjin River), Anseongcheon, Sapgyocheon, Geum River, Mankyeong River, Dongjin River, Yeoungsan River, Tamjin River, Seomjin River, Gawhacheon, Nakdong River(including West Nakdong River), Taewha River, and Hyeongsan River estuaries. The Regional 1st Class River scale estuaries are counted as four, i.e. Yeoungdeok Osipcheon, Samcheok Osipcheon, Gangneung Namdaecheon, and Yangyang Namdaecheon. While, the Regional 2nd Class River estuaries are arranged as the Province and counted as total 444; Jeonnam, Gyeongnam, Chungnam, Jeju Province have the 108, 94, 52, and 35 estuaries, respectively. The counted estuary numbers, however, can be slightly increased/decreased on what references are applied, e.g. whether or not including the streams lost estuary functions by the sea-dike construction or integrated nearby streams, and so on.

• The Research Journal of the Costume Culture
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• v.6 no.2
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• pp.36-44
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• 1998

The purpose of this study was to identify and to classify the names of costume colors of women of Silla. The results of this study can be summarized as follows; Until now scholars and researchers interpreted nine colors in Sam Guk Sa Ki as nine colors explained in the dictionaries. However, term, nine colors in the contexts did not refer to the literary meaning of nine colors such as blue, red, yellow, white, black, green, purple, pink, and navy blue as explained in the dictionaries. 'Nine colors' of Silla were women's costume colors which were specified in the royal edict in the texts. Thus, 'nine colors' of Silla had a specific meaning rather than literary meaning. 'Nine colors' of Silla women's costume were identified as red( ), yellow(黃), purple(紫), purplish pink(紫粉), gold powder(金屑), pink(紅), yellow powder(黃屑), dark pink(緋) and dark purple(滅紫). These 'nine colors' were actually prohibited colors in women's costume in the royal edict. Women from true bone, the highest class, were prohibited the use of tow colors of red and yellow out of nine colors. While women from four du pum and common class were forbidden the use of nine colors out of total of nine colors. Kinds and numbers of colors of costume were used as a means of differentiating the social class and rank of women in Silla. Also it was found that women of Silla favored red purple, pink tones and yellow color in their costume and these colors were fashionable colors among women of Silla. These fashionable costume colors of Silla women seems to be influenced by fashions of women of T'ang dynasty of China. Red, purple, pink, yellow and green were favorite colors of women of T'ang dynasty of China.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.220-231
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• 1985

In selected patients with occlusive lesions of coronary arteries, aortocoronary bypass grafting has been effective in reducing anginal symptoms and in increasing the patients` longevity. Between May, 1977, and December, 1983, 41 patients with coronary occlusive disease received aortocoronary bypass surgery at Yonsei University Medical Center in Seoul. Thirty-three were male and 8 were female. Their ages ranged from 33 to 70 years [average 531.6 years]. Of the 41 patients, 11 suffered from stable angina, 30 suffered from unstable angina and 4 suffered from a variant type of angina. Eleven patients had 1 diseased vessel, 11 patients had 2 diseased vessels, 19 patients had 3 diseased vessels, and 5 patients had a diseased left main coronary artery. A single graft was placed in 5 patients, a double graft was placed in 17 patients, a triple graft was placed in 11 patients and a quadruple graft was placed in 8 patients. Nineteen patients received a sequential graft [40 sites of 20 vessels]. The average internal diameter of the grafted distal coronary artery was 2.380.15, 1.630.13 mm on the left side and 3.200.20, 1.830.21 mm on the right side. Two operative deaths occurred in the early years of our experience. The mortality rate was 4.87% and there were no late deaths. Of the 39 survivors, 30 [76.9%] were Functional Class I [free of symptoms without medication], 7 [17.9%] were Functional Class II and only 2[5.2%] were Functional Class III during the follow up period [653.75 patient-months]. On the basis of this experience, we conclude that coronary artery occlusive disease is occurring in increasing numbers in Korea. Therefore, a concerted effort is needed to detect this disease and to manage the increasing number of patients suffering from it.

• Journal of the Korean Society of School Health
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• v.1 no.1
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• pp.103-113
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• 1988

The analysis of the visual impairment and refractive errors among 4,004 school children in Seoul in 1986 with ancilliary questionnaire on various socio-environmental and visual factors was conducted. The number of the student with subnormal vision (0.7 or less) was 1,552 (38,8 %), and the rate of subnormal vision was increased with the higher grading of the school classes. Rate of myopes among the 1,552 students vision 0.7 or less consists of 52 % in primary school, 83.5 % in middle school, and 94 % in high school, and they were increased with the higher grading of the school class. The acutest increase of rates were observed at the stages of 2nd year class of male, and 1st year class of female at the middle school. Among the glasses-wearer of myopic students of vision 0.5 or less, the rate of adequately corrected cases was 42.5 %, whereas the overcorrected in 6.8 %, and undercorrected in 49.3 %. The main reasons of glasses negligence among the non-possessor of glasses with the vision of 0.5 or less were indicated in prominence of numbers of' "no complaints without glasses" (42 %). "unawareness of visual disturbance" (20%), "annoyance with wearing glasses" (13.4%), and "no permission from parents" (11.5 %) rather than the "economical reasons". The amblyopic components were estimated 126 cases (3.2%) in combination of refractive errors. According to the analysis of ancilliary questionnaire, the-conclusion with the statistical significance was that the myopization of the children's eyes appeared susceptible with a number of socio-environmental factors including the eating habits, length of T.V. watching period and distance, reading distance and type of illumination during near work, and school achievement. The possibility of prevention in some extents of progress of the myopia following the improvement of the relevant environmental factors in younger stage of children would be considered as deducible one.

• School Mathematics
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• v.18 no.1
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• pp.85-103
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• 2016

This study was to find characteristics of argumentation derived from a discourse in a math-gifted 5 grade class, which was held for finding a Pick's formula using Geoboard function of TI-73 calculator. For the analysis, a video record of the class, transcript of its voice record, and activity paper were used as data and Toulmin's argument schemes were applied as analysis standard. As a result of the study, we found that the graphing calculator helped the students to create an experimental environment that graphing a grid-polygon and figuring out its area. Furthermore, it also provided a basic demonstration through 'data->claim' composition and reasoning activities which consisted of guarantee, warrant, backing, qualifier and refutal for justifying. The basic argumentation during the process of deriving the Pick's theorem by the numbers of boundary points and inner points was developed into a 'collective argumentation' while a teacher took a role of a conductor of the argumentation and an authorizer on the knowledge at the same time.