• Journal of architectural history
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• v.31 no.6
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• pp.7-16
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• 2022

Traditional Korean architecture and traditional ships maintained a close relationship with carpenters and tools because wood, the material, was common. This close relationship may have been from the time of ancient architecture and ancient ships. In previous studies, researchers proved the relationship between these two sides through historical records of traditional architecture and traditional ships. This study attempts to prove the structural association using existing remains. As a result, three structural similarities between traditional architecture and traditional ships could be found. First, the types of wood used are similar, and the tools and terms used are similar. Second, the method of distinguishing horizontal and vertical materials and the structure of wood and the method of forming wood are similar. Lastly, the ship carpenters mobilized for the construction of the palace mainly worked on long and curved materials such as the eaves and the ridge of a roof, because this was the work done when the ship was built. Therefore, it can be assumed that the roof structure they created resembles that of the ship.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.467-474
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• 2017

Each river confluence has the inherent hydraulic and mixing characteristics coming from its bathymetry and topography. It is necessary to make the measurement covering the spatial extent of studying area in order to catch these 2-dimensional intrinsic characteristics. This study focuses to investigate the hydraulic and mixing characteristics at the confluence of Nakdong and Geumho River, from field measurement of flow, water quality, and suspended particle distribution with ADCP (Riversurveyor M9), multi-parameter water quality sonde (YSI6600V2), and submersible system for in-situ observations of particle size distribution and volume concentration (LISST : Laser In-Situ Scattering & Transmissometry), respectively. From the results, it can be found that the field measurement of suspended particle and water quality distribution can be the useful approach to catch the hydraulic and mixing characteristics at a river confluence.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.20-27
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• 1989

This experiment was made to find the peripheral variations of annualring widths, the cell dimensions, microfibril angles and bulk densities within each annual-ring of horizontal-growing young tree of beech(Betul a platyphylla var. japonica) and Oak (Quercus variabilis) from the tension to the opposite side. Also a comparision between the features of the obnormal annual ring for horizontal-growing year and normal annual ring for the straight-growing years was made. The dimension of propotion of the element, the microfibril angles and the bulk density decreased or increased continuously toward opposite side which showed minimum or maximum value. The dimension of elements the microfibril angles and the bulk density decreased or increased continuously towards opposite side which showed minimum or maximum value. The dimension of elements. the microfibril angles and the bulk density in the normal annual rings were similar to those in the lateral woods. whereas were significantly more different in the tension wood than in the opposite wood. The features of typical opposite wood in the hardwoods were influenced by the locations within the inclined stems than effects of the decrease in the annual ring width. The oppostie woods in hardwoods did not conform to the tension wood and lateral wood. The abnormal annual ring included the opposite wood, lateral wood similar to normal wood and tension wood having specialized structure even in the same annual ring.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.379-382
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• 1991

Tree height at age 10 was used to estimate the statistical efficiencies of sampling size in the progeny test of Pinus koraiensis S. et Z. Experimental design was RCB design which consists of 25 half-sib families in each of three blocks. The number of families and blocks were fixed, therefore, the number of trees sampled per plot was the only factor that influences the environmental portion of the family mean height. Coefficient of variation, the estimate of the standard error of the family mean height, decreased with increase of sampling plot size, and became stable from 4-tree plot sampling (6.97%). The experimental error was significant from 7-tree sampling plot size. Nonlinear relationship (${\hat{Y}}=10.425e-^{0.073x}$ ; $R^2$=0.840) was found between the sampling plot size and the standard error of family mean height.

• The Journal of Korean Association of Computer Education
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• v.18 no.4
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• pp.55-62
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• 2015

Recommender systems through collaborative filtering has been utilized successfully in various areas by providing with convenience in searching information. Measuring similarity is critical in determining performance of these systems, because it is the criteria for the range of recommenders. This study analyzes distributions of similarity from traditional measures and investigates relations between similarities and the number of co-rated items. With this, this study suggests a method for selecting reliable recommenders by restricting similarities, which compensates for the drawbacks of previous measures. Experimental results showed that restricting similarities of neighbors by upper and lower thresholds yield superior performance than previous methods, especially when consulting fewer nearest neighbors. Maximum improvement of 0.047 for cosine similarity and that of 0.03 for Pearson was achieved. This result tells that a collaborative filtering system using Pearson or cosine similarities should not consult neighbors with very high or low similarities.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.107-112
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• 2014

The productivity and cost of clear cutting operations were examined to broaden our knowledge on the harvesting system in a Larix leptolepis stand of Korea. The harvesting system was divided into tree operations which were chainsaw (STIHL MS440) felling, tower yarder (Koller301-4) yarding and harvester (WOODY H50) processing. The average cycle time of felling, yarding and processing were 98 s/cycle, 245 s/cycle and 150 s/cycle. The total stump-to-pile operational productivity was 43.07 $m^3/hr$. The highest production activity was the felling 17.93 $m^3/hr$, followed by the productivity of processing 15.62 $m^3/hr$ and then by the productivity of yarding 9.52 $m^3/hr$. In addition the total stump-to-pile operational cost was 24,086 $won/m^3$. The highest cost activity was the yarding 14,557 $won/m^3$ (60.4% of the total cost), followed by the costs of processing 8,461 $won/m^3$ (35.2%) and then by the costs of felling 1,068 $won/m^3$.

• Journal of architectural history
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• v.26 no.4
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• pp.19-34
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• 2017

The purpose of this study was to comprehend the assignment and the procurement method of wood works' craftsman through the Salleung-dogamuigwes in royal tombs constructions in the late Joseon period. Following conclusions have been reached through the study. First, Carpenter and other nine craftsmen were introduced in carpentry works. The craftsmen were put in by occupation to maintain the quality of the government building construction by wood processing area. It was distinguished by frame member, Sujangjae, window framing wood, decorative member. Second, sawyer showed a sharp increase in the latter half of the 18th century and declined since the middle of the 19th century. This is closely related to the increase in demand for building materials and the growth of civilian wood products. As a maximum of 300 people have been assigned to the craftsmen in the woodwork, it can be seen that the work has been divided by the process. Third, the national carpenter was difficult to procure from the 17th century to the beginning of the 18th century. From the middle 18th century, the system procuring national carpenter was stabilized. In the 19th century, the input ratio of the national craftsmen seems to have decreased significantly and seems to have kept it at the minimum level. Forth, sawyer were procured through Seongonggam from the late 18th century through the mid 19th century. That means that the role of the sawyer had become important. Since Jogakjang is not a necessary manpower, it usually has civilian artisans.

• The Journal of Korean Association of Computer Education
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• v.19 no.4
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• pp.59-66
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• 2016

It has been studied to reflect the number of co-rated items for solving data sparsity problem in collaborative filtering systems. A well-known method of Jaccard index allowed performance improvement, when combined with previous similarity measures. However, the degree of performance improvement when combined with existing similarity measures in various data environments are seldom analyzed, which is the objective of this study. Jaccard index as a sole similarity measure yielded much higher prediction quality than traditional measures and very high recommendation quality in a sparse dataset. In general, previous similarity measures combined with Jaccard index improved performance regardless of dataset characteristics. Especially, cosine similarity achieved the highest improvement in sparse datasets, while similarity of Mean Squared Difference degraded prediction quality in denser sets. Therefore, one needs to consider characteristics of data environment and similarity measures before combining Jaccard index for similarity use.

• Composites Research
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• v.17 no.2
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• pp.41-48
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• 2004

"Phenolic composite", one of safety composites was chosen to build rolling stock in England while it was applied to building materials in London Underground facilities. This paper was written by Mr. Denver E. Brown. He emphasizes, from visibility and toxicity points of view, phenolic is the best and Mr. Forsdyke says, there is no question, passenger's lives are No. 1 issue, material recycling is not No.1! not No.1!

• Journal of Wetlands Research
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• v.15 no.1
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• pp.59-69
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• 2013

The numerical simulations were performed to analyze the advection-diffusion processes of dredging-induced turbidity plume using RMA2 and RMA4 models in Bunam reservoir, Seosan, Chungnam. Field survey was also performed to measure the turbidity using the multi water quality monitoring system (YSI6600EDS). In the field survey, the vertical and horizontal distributions of the turbidity were measured during the dredging operation in Bunam reservoir. RMA2 model was used to simulate the velocity distributions in both the whole domain and the 2nd part of Bunam reservoir. RMA4 model was also used to simulate the concentration distribution in only the 2nd part of Bunam reservoir, where the dredging work were conducted. The comparison of the simulation results with the field data for the advection-diffusion of the turbidity plume using the concentration ratio concepts shows that the numerical model can be applied to analyze the environmental impact of dredging works.