• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4717-4722
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• 2014

In shipyards, a large number of dog-pieces are used to align welding joints and prevent welding deformation in the block assembly stage. The huge working man-hours consumed in the working process of dog-pieces impedes the productivity growth of shipyards. In this study, an analysis method based on the experimental results was proposed to simulate the welding deformation of butt joints with a dog-piece setting. The simulation of welding deformation of a hull block joint was performed using the proposed analysis method. Finally, the proposed analysis method can be used to establish guidelines for the proper use of dog- pieces in the block assembly stage.

• Journal for History of Mathematics
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• v.21 no.4
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• pp.169-182
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• 2008

This study has been searching for reasoning process solving the problem effectively in activities related to meaningful classification of pieces and geometric properties with tangram. In activities using some pieces of tangram, we systematically came up with every solution in classifying properties of pieces and combining selected pieces. It is very difficult for regular students to do this tangram. In order to solve this problem effectively, we need to show that there are activities using the idea acquired in reasoning process. Through this process, we do not simply use tangram to understand he concept and play for interest but to use it more meaningfully. And the best solution an not be found by a process of trial and error but must be given by experience to look or it systematically and methods to reason it logically.

• IE interfaces
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• v.23 no.4
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• pp.337-348
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• 2010

The Bass model is the most widely used model in research of new product diffusion because it presents a nice explanation on the diffusion process of new products. However, it has a limitation that its performance of fitness is lower as the available data become less and also, the diffusion curve is bell-shape and so, it can not represent the various diffusion patterns. Recently, a two-pieces Bass model is developed and applied to analyze diffusion of 10 products. The results are encouraging in terms of fitness. However, diffusion pattern is not dealt with in the paper. In this paper, analysis of diffusion pattern is in depth addressed in two-pieces Bass model. It is shown that the diffusion curves are divided into 3 types with respect to the peak adoption rate and each type is divided into 2 types further. Takeoff time of a diffusion process is analyzed by using the inflection point and regime-change time where it represents the point that imitation and innovation parameters change. Empirical studies for 68 products(28 domestic products and 40 USA products) are performed to analyze the diffusion pattern. Findings are that diffusion patterns of all products except 1 USA product show type I and regime-change time becomes shorter as the introduction time of the product is later in domestic products and regime-change time can be regarded as a takeoff time in 47% of total 68 products.

• The Korea Journal of Herbology
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• v.28 no.1
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• pp.51-58
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• 2013

Objectives : As Daily Dose of Zizyphi Fructus was designated by the numbers in Treatise on Cold Damage Disease, estimation of Daily Dose was all different among researchers. The purpose of this study was to estimate exact Daily Dose of Zizyphi Fructus. Methods : We fixed the errors in various copy of Treatise on Cold Damage Disease and considered the meaning of the Bee Zizyphi Fructus(肥大棗) and general rules of Daily Dose in Treatise on Cold Damage Disease. So we reduced Daily Dose of Zizyphi Fructus, and compared this with the standard of Zizyphy Fructus in Pharmacopoeia of several Nation and Korean Forest Service. Results : Daily Dose of Zizyphi Fructus was generally 12 pieces; less was for prescriptions which scaled down the amount of ingredients prescribed in the originals; 15, 25, and 30 pieces were used when more was required. The medicinal part was the pulp of fructus, and the dosage of 12 pieces was respectively equivalent to 3 Ryang(兩), and 19.5 g. As defined in the Korean Pharmacopoeia Ninth Edition and standards of forest products by Korea Forest Service, Zizyphi Fructus was medium-sized, and weighs about 1.625 g if properly dehydrated. Conclusions : In short, the proper Daily Dose of Zizyphi Fructus in Treatise on Cold damage Disease was 12 pieces of Zizyphi Fructus and 19.5 g of its pulp, weighing three Ryang(兩). The pulp was estimated to be 1.625 g; it was medium-sized according to the present standard.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.249-258
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• 2020

This study aims to provide reference material for effective forest management techniques at the catchment scale, based on the field investigation of large woody debris (LWD) in 11 streams within a third-order forest catchment in Gangwon Province, Korea. To achieve this aim, we analyzed the morphological features of LWD pieces, and the storage and distribution status of LWD by stream order throughout the entire investigation. As a result, a total of 1,207 individual pieces of LWD were categorized into three types as follows: (ⅰ) 1,142 pieces (95%) as only trunk and 65 pieces (5%) as a trunk with root wad, (ⅱ) 1,015 pieces (84%) as non-thinned and 192 pieces (16%) as the thinned, and (ⅲ) 1,050 pieces (87%) as conifer and 157 pieces (13%) as broadleaf. Additionally, in-stream LWD loads (㎥/ha) decreased with increasing stream order, yielding 105.4, 71.3, and 35.6 for first-, second-, and third-order streams, respectively. On the other hand, the ratio of LWD jams to the total LWD volume increased with increasing stream order, yielding 11%, 43%, and 49% for first-, second-, and third-order streams, respectively. Finally, a comparison of the in-stream LWD load with previous studies in several countries around the world indicated that in-stream LWD load was positively correlated with forest stand age even though the climate, topography, forest soil type, forest composition, stand growth rate, disturbance regime, and forest management practices were different. These results could contribute to understanding the significance of LWD as a by-product of forest ecosystems and an indicator of riparian forest disturbance. Based on this, we conclude that advanced forest management techniques, including treatment of thinning slash and stand density control of riparian forest by site location (hillslope and riparian zone, or stream order), should be established in the future, taking the forest ecosystem and the aquatic environment from headwater streams to low land rivers into consideration.

• Sijohaknonchong
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• v.43
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• pp.149-175
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• 2015

There have been few researches about Christian imagination reflected in modern sijo. The purpose of this study was to provide basic information helpful to deeply understand Christian literature and clarify the history of Christian sijo literature. For this purpose, the study focused on pieces of sijo written by Seon Jeong-ju and Jang Sun-ha both of whom put out lots of sijo based on Christian imagination. The two poets are common in that they were born in the Japanese colonial period and started their career as a poet at an almost same time. First of all, how a sijo writer, Seon Jeong-ju applied Christian imagination to his pieces of sijo can be summarized as follows. As a poet and paster, Seon Jeong-ju wrote and published 6 volumes of sijo collection. His pieces of sijo were all written based on Christian imagination. Many of the pieces contain Christianity-related stories that were poetically represented through paradoxical imagination. Among pieces of sijo written by Seon Jeong-ju, some reveal enthusiasm for seeking after truth that he kept in mind as a clergyman and others, the poet's strong belief in the Resurrection. Next, Christian imagination that another sijo writer Jang Sun-ha reflected in his works can be briefed as follows. The poet published a sijo collection of his own in 2010. As one of the best representatives of the modern sijo circles, he is a veteran poet who is still creating pieces of sijo. Since he became a Christian in 1996, he has released more than 200 pieces of Christianity-based sijo including those contained in his sijo collection, "Introduction to Love Studies". Most of the Christian poets quoted words from the Bible or borrowed episodes described in the Book. In those poets, he uses imagination that is allusive to the confession of his faith and, in some cases implies his own views of eschatology. In conclusion, both Seon Jeong-ju and Jang Sun-ha wrote and published lots of sijo works on the basis of Christianity, and each of them built up his own world of Christian sijo. In many of the two poet's pieces of sijo, critical doctrines of Christianity and their desperate devotion to that religion are found. Both of them made remarkable poetic achievements, so they deserve being recognized as second to none in the history of Christian sijo literature.

• Journal of the Korean Society of Costume
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• v.59 no.5
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• pp.1-18
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• 2009

Due to the severe damages, it is very difficult to fathom out the original shape of the armor of Seong-ryong Ryu(1542-1607) right now. Ryu was a distinguished scholar official of his period, and his remaining armor has been designated as a National Treasure No. 460. This is a study of the types of the used scales, their positions used, the methods of their connections, and their hemmings, to figure out the original process of producing the armor. Based upon the research results, the remaining pieces of the armor are restored according to the discovered contemporary procedure of the armor. Then hypotheses are proposed for the three kinds of armor made up of long pieces, and three kinds of the armor of short pieces, and problems of the proposed hypotheses are considered for further studies. Hopefully this kind of approach shall serve as a ground stone for the better restorations of the scale armors of Joseon period in the future.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.61-77
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• 2016

This study is to understand the meaning, the location, and the construction of Hyeonhun (玄纁) through the records and relics of the Chosun Dynasty. Hyeonhun means farewell gifts for the dead. Hyeonhun was very personal and was considered to be essential ritual supplies. it was newly made for not only first funeral(初葬), but also the second funeral(改葬), was individually made as well as in the couple funeral(夫婦合葬). the Hyeonhun ritual was performed while dressed in a simabok(緦麻服). The ritual started with washing of the hands(盥手) and deep bowing(再拜) twice. The Hyeonhun was placed on the lid of the inner coffin among the 3 coffins in Chosun tomb's way. The Hyeon was placed on the right side and the Hun on the left side of the lid.(玄右纁左). Hyeonhun are comprised of one, two, five of ten pieces. Most of the excavated Hyeonhun were two pieces : Hyeonhunsokbaek(玄纁束帛) consist of ten pieces, of which six were Hyeons and four were Huns. The records indicated that the materials used to make Hyeonhun was silk, but the excavated relics satin and twill, single gauze in the excavated relics advanced than the records.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.48-56
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• 2009

In this paper, laser-assisted machining(LAM) has been employed to machine hot isostatically pressed (HIPed) Si3N4 work pieces. Due to little residual flaws and porosity, HIPed $Si_3N_4$ work pieces are more difficult to machine compared to normally sintered $Si_3N_4$ workpieces. In LAM, the intense energy of laser was used to enhance machinability by locally heating the workpiece and thus reducing yield strength. In experiments, the laser power ranges from 200W to 800W and the diameter of work pieces is 16mm. While machining, the surface temperature was kept nearly constant by laser heating except for a short period of rise time of max. 58 seconds. Results showed as feed rate increases the surface temperature of $Si_3N_4$ workpieces decreases slightly, whereas the effect of depth of cut is disregardable. With a laser power of 800W, achievable maximal depth of cut as 0.7mm and feed rate was 0.03mm/rev.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1059-1063
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• 2010

Shimming is an important technique in development of nuclear magnetic resonance (NMR) magnets where image resolution is highly dependent on magnetic field homogeneity. Classically, shimming may be categorized into two types: 1) active shimming that incorporates with extra coils and precise tuning of their currents; and 2)passive shimming that incorporates with pieces of steel placed in a bore of a main magnet and their uniform magnetization under homogeneous external fields. Additional magnetic fields, produced by the coils and/or the steel sheets, compensate original magnetic field from the main magnet in such a way that the total field becomes more homogeneous. In this paper, we developed a passive shimming method based on linear programming optimization. Linear programming is well known to be highly efficient to find a global minimum in various linear problems. We firstly confirmed the linearity of magnetization of ferromagnetic pieces under a presence of external magnetic fields. Then, we adopted the linear programming to find optimized allocation of the steel pieces in the inner bore of a main magnet to improve field homogeneity.