• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.362-369
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• 2017

This study was carried out to provide basic data for active control of the anticipated damage through investigation and analysis of geographical and spatial occurrence distribution of oak wilt disease area. The damage of oak wilt disease was analyzed by investigating all the damage trees caused by oak wilt disease from 2011 to 2015 in three areas of Gwangtan-myeon, Paju-si, Gyeonggi -do. As a result, the closer to the ridge the more damage of the oak wilt was generated. Therefore, it is necessary to select the central management area from 0 to 40 m based on the ridge line for more effective control, and to intensively control the area. Also, it is difficult to predict the occurrence of damage by the slope because the damage situation represent differently by the region. By the diameter class, it was analyzed that the number of damaged trees was the largest in the average diameter class with the most number of the trees in each region.

• 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.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.357-374
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• 2012

Considerable uncertainties are included in ground properties used for tunnel designs due to the limited investigation and tests. In this study, a back analysis was performed to find optimal ground properties based on artificial neural network using both face mapping data and convergence measurement data. First of all, the rock class of a study tunnel is determined from face mapping data. Then the possible ranges of ground properties were selected for each rock class through a literature review on the previous studies and utilized to establish more precise learning data. To find an optimal training model, a sensitivity analysis was also conducted by varying the number of hidden layers and the number of nodes more minutely than the previous study. As a result of this study, more accurate ground properties could be obtained. Therefore it was confirmed that the accuracy of the results could be increased by making use of not only convergence measurement data but also face mapping data in tunnel back analyses using artificial neural network. In future, it is expected that the methodology suggested in this study can be used to estimate ground properties more precisely.

• Journal of Korean Library and Information Science Society
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• v.15
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• pp.179-205
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• 1988

The purpose of this research is to analyze the differences between electronical engineering class in KDC3 and electronical engineering class in DDC 19. The results of the study can be summarized as follows ; 1. The characteristics of the classification items in classification schemes of the electronical engineering fields is that KDC is classified by the vacuum tubes, electron tubes, special tubes, computers etc and DDC is classified by the microwave electronics, short-and long-wave electronics, X-ray and gamma-ray electronics, computers etc. 2. There is a blank in KDC and there are three blanks in DDC of the electronical engineering fields, but the total classification items number is much more in DDC than in KDC. This means that DDC is more classified than in the special classification items. 3. Classification items over 70% in the total classification items of computer fields in KDC, are classified a classification items of the short-and long-wave electronics in DDC. 4. There is a blank of computer fields in KDC and there are three blanks of computer fields in DDC, but the total classification items are many eighteen items. This means that DDC is more classified than KDC. 5. The sections of computers in DDC were established the 621.38195 classification item and the subsection of analogue computers in DDC were established the 621.381957 classification item and the subsection of digital computer in DDC were established the 621.381958 classification item. As we have seen, because of the development in technology and the subdivision of knowledge, the number of items is increased, and the terminology also become simplified and specified in the field of electronic engineering in KDC and DDC.

• Journal of Korean Society of Archives and Records Management
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• v.15 no.3
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• pp.29-54
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• 2015

This study aims to propose an education program using the records and archives of the May 18th Democratic Uprising, which are large in number and have diverse provenance. The PBL model, which is a basic model for this program, is appropriate for suggesting a number of records and inducing the use of archives. This program is based on the rule of PBL but is divided into two parts: a pre-class level and an in-class level. The archives list for this program is selected from the archives map, which consists of a horizontal axis of provenance and a vertical axis of creation time. The expected effects of this program is to vitalize and expand the use of archives and to inspire a student's historical thinking. This program is meaningful in proposing a proposed education program using the records and archives of a historical event and the probability to use in a real class.

• Journal of Service Research and Studies
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• v.4 no.2
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• pp.11-19
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• 2014

This study simulates cases with 20, 30, 40, 50, 60 and 100 students and 6 values as the parameter of mu. Using the simulation, an analysis was made of how the number of students that couldn't concentrate during class increased over the duration of time. When normalizing the difference in student number when the value of mu is constant, there was a decrease in percentage over time. It also showed a change in percentage when the value of time is fixed while the value of mu changes. Based on the result values, by estimating the mu value with the class atmosphere to predict the outcome and improve the lecture.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.254-261
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• 1994

This study was conducted to investigate and interpret the stand structure of Korean Red pine (Pinus densiflora) stands in Kangwon province, so as to provide basics information for effective forest management. The results obtained in this study were as follows : 1. Number of trees distribution for each diameter class have left nonsymmetrical in Gosung districts, but symmetrical distribution in Pyungchang districts. 2. Height curve for D.B.H. Distribution becames liner shape in Pyungchang districts that more higher than Gosung districts. 3. Stand volume and number of trees per ha in Pyungchang districts are higher than Gosung districts. 4. D.B.H. growth increments during recent 5 years at large D.B.H. class has much lager than low D.B.H. class. 5. Total growth increments of D.B.H., height and volume in Pyungchang districts are or the higher than Gosung districts overtimes 15 years later.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2839-2846
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• 2014

New VHF band for use in VDE is determined by WRC-12 due to the overload of AIS VDL, and the system characteristics of the VDE is recommended as ITU-R M. 1842-1. CS-TDMA, a multiple access method of AIS class B, is recommended as that of the VDE. It is inefficient for CS-TDMA just applying the report interval used in AIS class B to transmit high speed data with higher payload in the aspect of efficiency. In this paper, a simulation is executed in order to determine adequate report interval according to the number of active ships that affects directly network traffic. To this end, the performance of CS-TDMA, which includes the number of received packets, reception success rate, channel utilization, and collision rate, is investigated via a simulation.

• The Mathematical Education
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• v.43 no.2
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• pp.115-137
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• 2004

In this paper, we verified the effect and appropriateness of the scheme to cure the math. disliking disposition which is the cause of underachievement in learning. We choose 3 middle schools as the subject of experiment for this research. Each experiment class consists of 27∼30 students(underachievers) whose final test results of 1st school year in the middle school are 30∼60 points. In this case, we also select some middle level students whose test results are more than 60 points for the normal experimental condition. For this research, we developed the suitable test materials to cure the mathematics disliking disposition of underachievers. We applied those test materials to the experiment schools during 2.5 months and we analysed the variation of disliking disposition, the variation of math. dislike students' number and the cure rate of the math. disliking disposition. From the results of this experimental study, we find that the factors of teacher and math recognition environment have only the significant difference of math. disliking disposition between experiment class and comparison class under the 5% significance level in one middle school. We understand that this results caused by teachers' careful advice and guidance in that middle school. We also find that the number of student who dislike mathematics decreased in two middle schools. Furthermore 50% of math. disliking dispositions are cured for 9 disliking factors in the lower grade group(the group of underachievers) and as a whole, we can see that 50% of cure rate for the 7 factors of math. disliking in two middle schools. So we can understand that the experiment of our research was performed successfully in two middle schools. In this research, we find out that the scheme to cure the disliking dispositions for the factors of math. disliking depends on the factors of teacher who take charge of cure. So teachers must take interest in and must have careful concern to students and their math. disliking.

• Journal of the Korean Institute of Educational Facilities
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• v.27 no.3
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• pp.33-39
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• 2020

The purpose of this study is to understand the classroom facilities of England and USA in the 19th century. This kind of study can provide the meaning of past, present, and future on classroom facilities. The results of the study are as follows. First, England classroom in the 19th century was made up of a large space, a gallery, that could teach a large number of students at the same time. Second, the classroom facilities of USA in the 19th century were developed by reformers for the purpose of training the labor force of educational thought and industrial development. Third, some characteristics of classroom facilities of England and USA in the 19th century were also found in school facilities of Korea at the same time. Fourth, large gallery classes began to disappear in the mid-19th century and were transformed into small 'class' facilities to improve efficiency. Fifth, the word 'class' did not appear as a substitute for the school, but as a meaning of subdividing within the school. Sixth, these classrooms consisted of smaller classes, and they began to create and teach common and unified curriculums to harmonize the differences between classes and to manage all students efficiently and effectively. Seventh, the basis of the classroom of England and USA in the 19th century was the design of one teacher to efficiently teach a large number of students, and there was a difference in size, but the current classroom facilities have been maintained to some extent. Eighth, since the end of the 19th century, the compulsory education system has been discussed and gradually introduced, requiring more schools and classroom facilities, and labor and capital have been emphasized by the development of industrialization. Ninth, follow-up studies are needed to analyze how classroom facilities have been universally transformed since then, based on class facilities in the 19th century, and what educational, social and political contexts have been added in the process.