• Korean Journal of Mineralogy and Petrology
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• v.33 no.2
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• pp.99-114
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• 2020

The characteristics of the Brazilian tensile strengths(σ_t) parallel to the rock cleavages in Jurassic granite from Geochang were analysed. The evaluation for the six directions of rock cleavages was performed using the parameter values on microcrack length and the above strength. The strength values of the five test specimens belonging to each direction were classified into five groups. The strength values of these five groups increase in order of group A < B < C < D < E. The close dependence between the above microcrack and strength was derived. The analysis results of this study are summarized as follows. First, the chart showing the variation and characteristics of strength among the three rock cleavages were made. In the above chart, the strength values of six directions belonging to each group were arranged in order of rift(R1 and R2), grain(G1 and G2) and hardway(H1 and H2). The strength distribution lines of the five groups concentrate in the direction of R1. And the widths among the above five lines indicating strength difference(Δσ_t) are the most narrowest in R1 direction. From the related chart, the variation characteristics among the two directions forming each rock cleavage were derived. G2(2)-test specimen shows higher value and lower value of the difference in strength compared to the case of G1(1)-test specimen. These kinds of phenomena are the same as the case between the test specimen H2(2) and H1(1). The strength characteristics of the above test specimens (2) suggest lower microcrack density value and higher degree of uniformity in the distribution of microcracks arrayed parallel to the loading direction compared to those of test specimens (1). The six strength values belonging to each group were arranged in increasing order in the above chart. The strength values of the test specimens belonging to both group D and E appear in order of R1 < R2 < G1 < H1 < G2 < H2. Therefore, the strength values of group D and E can be indicator values for evaluating the six directions of rock cleavages. Second, the correlation chart between slope angle(θ) and strength difference(Δσ_t) were made. The values of the above two parameters were obtained from the five strength distribution lines connecting between the two directions. From the chart related to rift plane(G1-H1, R'), grain plane(R1-H2, G') and hardway plane(R2-G2, H'), the slope values of linear functions increase in order of R'(0.391) < G'(0.470) < H'(0.485). Among three planes, the charts related to hardway plane show the highest distribution density among the five groups. From the related chart for rift(R1-R2, R), grain(G1-G2, G) and hardway(H1-H2, H), the slope values of linear functions increase in order of rift(0.407) < hardway(0.453) < grain(0.460). Among three rock cleavages, the charts related to rift show the highest frequency of groups belonging to the lower region. Taken together, the width of distribution of the slope angle among the three planes and three rock cleavages increase in order of H' < G < R' < R < G' < H. Third, the correlation analysis among the parameters related to microcrack length and the tensile strengths was performed. These parameters may include frequency(N), total length(Lt), mean length(Lm), median length(Lmed) and density(ρ). The correlation charts among individual parameters on the above microcrack(X) and corresponding five levels of tensile strengths for the five groups(Y) were made. From the five kinds of correlation charts, the values of correlation coefficients(R²) increase along with the five levels of strengths. The mean values of the five correlation coefficients from each chart increase in order of 0.22(N) < 0.34(Lt) < 0.38(ρ) < 0.57(Lmed) < 0.58(Lm). Fourth, the correlation chart among the corresponding maximum strength for group E(X) and the above five parameters(Y) were made. From the related chart, the values of correlation coefficient increase in order of 0.61(N) < 0.81(Lt) < 0.87(ρ) < 0.93(Lm) < 0.96(Lmed). The two parameters that have the highest correlations are median length with maximum strength. Through the above correlation analysis between microcrack and strength, the credibility for the results from this study can be enhanced.

• Research in Plant Disease
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• v.29 no.2
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• pp.168-173
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• 2023

Agricultural antibiotics are widely used to inhibit the growth of phytopathogenic bacteria involved in plant diseases. However, continuous antibiotic overuse in crop production may lead to the development of antibiotic resistance in phytopathogenic bacteria. This study was conducted to evaluate the resistance to three different agricultural antibiotics (oxytetracycline+streptomycin, streptomycin, and validamycin A) in 91 strains of phytopathogenic bacteria including Pectobacterium carotovorum, Pseudomonas syringae pv. actinidiae, Clavibacter michiganensis subsp. michiganensis, C. michiganensis subsp. capsici, and Xanthomonas arboricola pv. pruni. Bacterial growth in the presence of various concentrations of validamycin A was also assessed spectrophotometrically by analyzing the optical density. All strains did not grow when the cells were exposed to oxytetracycline+streptomycin or 100× of streptomycin. However, among the 91 strains, 4% and 2% strains showed bacterial growth at the concentrations of 1× and 10× of streptomycin, respectively. Furthermore, 97%, 93%, and 73% strains were resistant to the 1×, 10×, and 100× of validamycin A, respectively, and especially, P. carotovorum contained the highest resistance to the validamycin A. Minimum bactericidal concentration values of validamycin A did not correlate with the patterns of agricultural antibiotic resistance. Further studies are needed to understand the incidence and development of antibiotic resistance in phytopathogenic bacteria.

• Journal of the Korean Geotechnical Society
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• v.26 no.3
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• pp.35-45
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• 2010

The mechanism of load transfer by punching shear in pile-supported embankments is investigated. Based on the geometric configuration of the punching shear observed in sand fills on soft ground, a theoretical analysis is carried out to predict the embankment loads transferred on a cap beam according to punching shear developed in pile-supported embankments. The equation presented by the theoretical analysis was able to consider the effect of various factors affecting the vertical loads transferred on the cap beam. The reliability of the presented theoretical equation is investigated by comparing it with the results of a series of model tests. The model tests were performed on cap beams, which had two types of width; one is narrow width and the other is wide width. Sand filling was performed through seven steps. Two types of loading pattern were applied at each filling step; one is the long-term loading, in which sand fills at each filling step were kept for 24 hours, the other is the short-term loading, in which sand fills at each filling step were kept for 2 hours. The vertical loads measured in all model tests show good agreement with the ones predicted by the theoretical equation. Finally, the predicted vertical loads also show good agreement with the vertical loads measured in a well-instrumented pile-supported embankment in field, where cap beams were placed on too wide space.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.1
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• pp.51-55
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• 2009

Volar rotatory dislocation of the proximal interphalangeal joint(PIP) of the finger is rare. We report a female judo player who had volar rotatory dislocation of the PIP joint of the middle finger. She had dislocation of PIP joint total 4 times. At operation, the central tendon was identified as being distension, with the ulnar collateral ligament ruptured. The ruptured ulnar collateral ligament was interposed within the joint. The ruptured ulnar collateral ligament was repaired and extensor expansion was repaired. At last follow-up, she didn't have recurrent dislocation during judo. Accurate diagnosis, early intervention and progressive rehabilitation of this injury are very important as other dislocations.

• Journal of Advanced Navigation Technology
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• v.16 no.1
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• pp.96-102
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• 2012

The goal of mobile internet system is to provide a high-data-rate, low-latency and optimized packet radio access technology supporting flexible bandwidth deployments. Therefore, network architecture is designed with the goal to support packet-switched traffic with seamless mobility, quality of service and minimal latency. An important requirement for the mobile internet system is improved cell-edge BER performance and data throughput. This is to provide some level of service consistency in terms of geographical coverage as well as in terms of available data throughput within the communication coverage area. In a cellular system, however, the signal to interference plus noise power ratio gap between cell-center and cell-edge users can be of the order of 20 [dB]. The disparity can be even higher in a communication coverage limited cellular system. This leads to vastly lower data throughputs for the cell-edge users relative to cell-center users creating a large QoS gap. This paper proposes a analytical approach that tries to reduce inter-cell interference, and shows the SIR and BER performance according to the OFDM system parameters in mobile Internet environment.

• Journal of Information Management
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• v.32 no.1
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• pp.23-49
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• 2001

The purpose of this study is to examine how corporate names are treated in the OPACs in Korea, and to find out how well the authority control is implemented. A corporate body often has different names and different forms of names which should be properly linked in the OPACs. Without the help of either references or internal links among such names and forms of names in the OPACs, users are likely to fail in getting the right results, In this study, the OPACs from the five major libraries, the National Assembly Library, KISTI, Yonsei University, the National Central Library, and the KERIS were examined. Major common findings include (1) the lack of consistency in applying cataloging rules, (2) the lack of proper authority control in treating corporate names, and (3) the lack of references or links among names and variant forms of names. Because of the small scale of this study, more comprehensive and thorough study seems to be needed. However, the overall improvement of cataloging practices and application of authority control is strongly suggested, based upon the findings.

• Journal of the Society of Disaster Information
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• v.9 no.3
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• pp.358-364
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• 2013

Conventional disaster resources management systems among the several institutes are not mutually connected. In case of NDMS(National Disaster Management System), the data of the system is confined to the resources of the local governments and not connected with any other disaster resource management systems. Therefore, it is difficult to find the needed resources, when the large scale disaster is occurred. In this paper, we developed the integrated model of the distributed resources management framework considering the current resource management environment among the institutes. It is loosely coupling model under the centralized system, called IDRM(Integrated Disaster Resource Manager). The system will be verified with the test sites including Korea Expressway Corporation, JeonBuk local government, and Korea Construction Equipment Association. Via the field testing, the system will be the base of the real available system in the future.

• Communications of Mathematical Education
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• v.29 no.3
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• pp.465-489
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• 2015

The purpose of this study is to suggest implications for the development and revision of future teaching materials for mathematically gifted students by using network text analysis of secondary mathematics materials. Subjects of the analysis were learning goals of 110 teaching materials in a gifted education center in science attached to a university from 2002 to 2014. In analysing the frequency of the texts that appeared in the learning goals, key words were selected. A co-occurrence matrix of the key words was established, and a basic information of network, centrality, centralization, component, and k-core were deducted. For the analysis, KrKwic, KrTitle, and NetMiner4.0 programs were used, respectively. The results of this study were as follows. First, there was a pivot of the network formed with core hubs including 'diversity', 'understanding' 'concept' 'method', 'application', 'connection' 'problem solving', 'basic', 'real life', and 'thinking ability' in the whole network from 2002 to 2014. In addition, knowledge aspects were well reflected in teaching materials based on the centralization analysis. Second, network text analysis based on the three periods of the Mater Plan for the promotion of gifted education was conducted. As a result, a network was built up with 'understanding', and there were strong ties among 'question', 'answer', and 'problem solving' regardless of the periods. On the contrary, the centrality analysis showed that 'communication', 'discovery', and 'proof' only appeared in the first, second, and third period of Master Plan, respectively. Therefore, the results of this study suggest that affective aspects and activities with high cognitive process should be accompanied, and learning goals' mannerism and ahistoricism be prevented in developing and revising teaching materials.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.829-844
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• 2013

This study performed comprehensive tests on the four hypotheses on the capital structures for the firms listed in the KOSPI during the period from 2006 to 2011. It may be of concern to find any financial profiles on firms' leverage across the book- and market-value bases since there was relatively little attention drawn to any financial changing profile of the leverage surrounding the period of the pre-and the post-global financial crises. The findings of this study may also be compared with those of the previous related literature, by which it may be expected to enhance the robustness and consistency of the results across the different classifications on capital markets. It was found that three explanatory variables such as PFT, SIZE, and RISK, were found to be the statistically significant attributes on leverage during the tested period. Moreover, the outcome by the Fisher Exact test showed that a firm belonging to each corresponding industry may possess its reversion tendency towards the industry mean and median leverage ratios.

• Food Science and Preservation
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• v.10 no.1
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• pp.70-74
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• 2003

The distribution of mesophilic and thermophilic bacteria in milled rice was not different according to growing land and variety of rice. However, The number of these bacteria were abundant in milled rice of lower milling degree or longer storage period. The growth of thermophilic bacteria in cooked rice of electric rice cooker was rapidly increased during storage of lower temperature below 75 $^{\circ}C$. Thermophilic bacteria were not appeared just after cooking. After cooked rice was stored far 18∼24 hon thermophilic bacterial growth was rapidly increased by changing spore to vegetative cell. The positive relation between cell number of thermophilic bacteria and occurrence of off-odor was slightly observed. The number of thermophilic bacteria in upper cooked rice of oven and was higher than those in inner and lower cooked rice. Major volatile compound of milled rice cooked and stored in electric rice cooker was hexanal oriented from rice. After long storage, it was confirmed that furan was major volatile compound as off-odor.