• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.4
• /
• pp.296-302
• /
• 1994

To alter the paddy field to upland, mole drainages were constructed under 30cm of the surface of(Jeon buk silt loam) which is not appropriate for cultivation of upland crops. Intervals of the moles were 50cm, 100cm and 150cm and diverted to upland for soybean cultivation. By construction of the mole drainage, about 75% to 45% of the rainfall was drained and the ground water level was maintained below 40cm. After a year of drainage, the blocky surface was changed to granular or nutty structure which is common in upland fields. Oxidation was progressed to the deep layer because of soil dryness. Soybean yield were increased by 11% to 22% in the mole drained plots, but wet injury was occurred in the nontreated check plot with relatively poor growth status.

• Journal of the Korean earth science society
• /
• v.32 no.1
• /
• pp.73-83
• /
• 2011

A new method was developed to better understand the principle of Coriolis force. We also investigated the understanding of 5 10th grade students and analyzed their responses. Since no clear explanation about the nature of a rotating disk is provided in school textbooks, it tends to be misunderstood as the earth surface revolving on its axis pointing to the North Pole. This study was carried out focusing on the fact that a rotating disk is the tangential plane at arbitrary latitude. Results showed that there are changes in students' conceptions on the principle of Coriolis force with a new understanding of the rotating disk. In conclusion, a new method used in this study helped students better understand the link between Coriolis force and rotating disk. The method would be helpful to clarify the principle of Coriolis force in school science.

• Journal of Korean Society of Forest Science
• /
• v.99 no.6
• /
• pp.802-807
• /
• 2010

The objective of this study was to estimate potential of domestic long-term wood supply by using fuzzy linear programming (FLP). In order to construct a numerical formula model, maximization of total timber production was used for the objective function. Size limit of harvesting and sustained yield were used as the constraints. The results of comparison between LP and FLP were shown that LP is more suitable than FLP in terms of the amount of timber production and final forest stock. However, as long-term sustained yield was limitedly achieved by using LP, FLP was more desirable for prediction of potential wood supply. According to the results of this study, the potential of annual domestic wood supply was estimated about 10.5 million cubic meters. Gyeong buk, Jeon nam, Gangwon and Gyeong nam province were highly ranked in order of provincial potential of wood supply.

• The Mathematical Education
• /
• v.45 no.3 s.114
• /
• pp.319-343
• /
• 2006

The purpose of this study is to investigate how fifth and sixth graders recognize average and to find out suggestions for teaching/learning methods of average by examining which difference there is depending on the way of the word problem presentation. For the this purpose, was conducted experiment study with the way of the world problem presentation set up as experimental treatment. The conclusions drawn from the results obtained in the this study were as follows : First, since students who did not learn the regular course of average had various informal concepts already, it is needed to consider handling more various concepts of average in order to enable students to expand flexible thoughts. Second, compared with fifth and sixth graders showed a wide difference in informal concepts of average depending on the way of the word problem presentation. In expect data with given average, concepts of mean as algorithm, balance point, and mode indicated similar percentage, while in estimate average with given data, the percentage of students who showed the concept of mean was very high at 67.6%. That may be because problems related to mean in the current textbooks are items of 'estimate average with given data', so in types of 'estimate average with given data', students solve questions with mean as algorithm without considering situations of problems. This result suggests that it is necessary to diversify the way of the word problem presentation even in textbooks. Third, as a result of analyzing informal concepts of average, there was significant difference in grades. In addition, the results suggested that there would be difference in the concepts of average depending on gender or attributes of discrete quantity and continuous quantity.

• Korean journal of applied entomology
• /
• v.19 no.2 s.43
• /
• pp.67-72
• /
• 1980

A mosaic virus disease of ginger plant was investigated to determine its virus group on the basis of host range, physical and chemical properties, serological behavior and electron-microscopic morphology. The disease gave rise to yellowsih and dark-green mosaic on the leaves in the early stage and stunted all the leaves as well as rhizomes in the late stage. In the field about 43\% of the plants were observed to be diseased The disease was able to be artificially infected to the ginger plants by the sap and transmission as well as to 23 other species of plants which were known to be the CMV susceptible plants by the sap transmission; Chenopodium amaranticolar, Nicotiana tabaccum var. Havana, cow pea, cucumber, tomato,... etc. The dilution end point of the virus ranged $10^{-4}-10^{-5}$ and the thermal inactivation point $65-70^{\circ}C$. Serological test showed a positive reaction by a CMV antiserum. An electron microscopy of the purified virus showed that the virus particles were spherical with a diameter of $28-32m\mu$. Virus particles from the infected tissue were observed to be free or aggregated in the mesophyll tissue of artificially infected tobacco plant. The mosaic disease of ginger plants were conclusively suggested to the CMV group.

• Journal of Korean society of Dental Hygiene
• /
• v.13 no.6
• /
• pp.1005-1014
• /
• 2013

Objectives : The purpose of the study is to obtain the basic data for an industrial oral health project enhancing the quality of life and oral health. Methods : Questionnaire consisted of 17 questions including 7 questions of general characteristics, 5 questions of oral health awareness, and 5 questions of the behavior of oral health. A self-reported questionnaire was carried out from September 1 to September 28, 2012, The subjects were 400 male and female sanitation workers in private corporations in Jeonju. A total of 354 questionnaires were analyzed using SPSS windows ver. 12.0 (SPSS Inc. Korea). Results : The majority of the subjects were male in 50's. Temporary contract workers are older aged and 2 to 5 years of career workers were the majority of the cleaners. Average monthly income was less than 2 million Korean Won. Those who had a higher academic background and permanent position tended to have oral health knowledge (p<0.05). Female workers had healthier subjective oral health status than male workers. Those who were in older age, single, temporary position, and 2 to 5 years of career tended to have healthier subjective oral health status (p<0.05). Those who were in older age, married, and long period of employment were worrying about their health (p<0.05). The subjective oral health knowledge was high in 49.7% of the workers because they were not able to brush teeth during work hours. They were able to brush their teeth only after dinner. It was low in female and older aged workers (p<0.05). The brushing method included a combination of top to bottom and from the side to side. Conclusions : This study showed the influencing factor of oral health in street workers. Work environment, education, age, monthly income, and types of employment were the important factors to oral health care. It is necessary to provide the right oral health care program for the workers in the near future.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.1
• /
• pp.21-28
• /
• 2005

In this paper, we studied resolution to the FBP(Filtered Back-Propagation) tomographic image reconstruction algorithms. In order to analyze the resolution to the tomographic images, we derived ambiguity function to this algorithm which can be reconstructed from the improved FBP image reconstruction algorithm by using fixed coordinate system practically. Through simulation using this function, we determined the lateral and depth resolution quantitively and then analyzed respectively. Simulation results show that the lateral and depth resolution to the improved FBP image reconstruction algerian was determined $0.27\lambda\;and\;0.70\lambda$ at the 3dB, and also $0.89\lambda\;and\;0.96\lambda$ at the 6dB respectively. This results proved that improved FBP reconstruction algorithms for diffraction tomography of incident planar wave is useful to developed the tomographic image system, analyze the resolution to the tomographic images, we derived ambiguity function to this algerian which can be reconstructed from the improved FBP image reconstruction algorithm by using fixed coordinate system.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.1
• /
• pp.27-35
• /
• 2020

Filefish Thamnaconus modestus has seen a sharp decline in their catch, we must strive for continuous resource management. We investigated the maturation and spawning of T. modestus by trawl net and set net from January 2018 to November 2019, off Jeju Is. and in coastal waters of North Gyeongsang Province's Korea. We analyzed monthly change total length (cm), gonadosomatic index (GSI) and maturity stages, egg diameter (mm), the relations fecundity and total length. GSI for Jeju Is. was the highest in April (3.17, 2.43), and decreased from July to 1.73 in August and GyeongBuk's GSI was the highest in Apri l (1.86, 2.58), followed by the high in May and the sharp decline in September, which is 0.23. Using a histological method, the annual reproductive cycle of T. modestus can be divided into 5stage in females; the early growing stage (Jan.-Mar.), late growing stage (Apr.-May), Mature stage, spent stage (Oct.), Recover and resting stage (Nov.-Jan.).We estimate the TL at 50% maturity as 24.1cm for female, fecundity ranged from 560,044 eggs at 23.4cm total length to 1,580,387 eggs at 36.6.cm TL.

• Journal of the Korean School Mathematics Society
• /
• v.16 no.4
• /
• pp.863-882
• /
• 2013

Shanghai has been reported as the highest performing countries(economies) in PISA 2009 and PISA 2012. In this reason, we reviewed literatures related to educational system of Shanghai focusing on the mathematics education. Additionally, we analysed the results of PISA 2009 of mathematics domain between Korea and Shanghai to compare some differences between two countries. As a result, we discovered the followings: 1) Comparing with Shanghai students, Korea students attained low performance in every sub-categories of mathematics abilities indicated in the PISA framework. 2) In PISA 2009 Framework, Korea students produced low achievement than Shanghai students in sub-categories of "reflection". 3) In PISA 2012 Framework. Korea students attained low performance than Shanghai students in sub-categories of "formulating". Consequently, it gave us insight into the idea that school mathematics in Korea should use authentic context to help students improve their competencies "reflection" and "formulating".

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3321-3330
• /
• 2009

This research was about influence on parenting by parent attachment. The subjects were W university students 223 of Jeon-buk province. The questionnaire included Inventory of Parent and Peer Attachment(IPPA) and parenting perception. Data were analyzed by Pearson's correlation and Stepwise. The findings were as follows: First, the relationship between parent(mother and father) attachment and parenting perception was found to a positive relationship. especially, communication and reliability of parent attachment. But between isolation of parent attachment and parenting perception was found to a negative relationship. Second, the parenting perception influenced by father's reliability among of parent attachment and the next was mother's communication.