• Research in Plant Disease
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• v.29 no.1
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• pp.1-10
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• 2023

The establishment of a laboratory assay and a greenhouse assay was conducted for evaluating the pathogenicity of Macrophomina phaseolina causing soybean charcoal rot established. In the laboratory assay, microsclerotia and hyphae were used as inoculum. In the laboratory assays using microsclerotia as an inoculum, disease incidences of M. phaseolina NSW17-108 and HSM17-034 were higher at 35℃ than 25℃. Of the two isolates NSW17-108 and HSM17-034, the disease incidence of HSM17-034 isolated from diseased sesame is higher than that of NSW17-108 isolated from diseased soybean. When the mycelia of M. phaseolina were used as an inoculum, the disease incidence of NSW17-108 and HSM17-034 at 35℃ exceeded 80% even after only 5 days of inoculation. Even at 25℃, furthermore, that of HSM17-034 exceeded 80% 5 days later. In the pathogenicity assays at a greenhouse, toothpicks where microsclerotia were produced or microsclerotia harvested from potato dextrose agar medium were used as an inoculum. In all greenhouse assays, M. phaseolina NSW17-108 and HSM17-034 showed 40-60% of disease incidences 35-65 days after inoculation with the pathogen, depending on the inoculation method. Between the two isolates, the pathogenicity of HSM17-034 was stronger than that of NSW17-108, and this result was consistent with laboratory assay results. Since the laboratory and greenhouse test methods tested in this study have different advantages and disadvantages depending on each test method, it is thought that the test method that can meet the purpose of the study should be selected and used.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.99-110
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• 2009

In order to provide the design criteria, the characteristics of consolidation for soft ground improvement have been investigated using the field banking test performed by the vertical drain method at the northern container section in Busan New Port. Field test results indicated that the estimated degree of consolidation in design stage decreased by about 7% compared with the measured one. This difference is attributed to the fact that the conservative geological properties were applied with relatively high amount of maximum clay mixture ratio during the design stage. Based on this findings, another laboratory oedometer test was implemented to consider various combination of mixture ratio. It was found that the consolidation degree increased in accordance with the increase of sand/silt mixture ratio. Also, the proportion of 10%, 50%, and 40% for sand, silt, and clay, respectively, was observed as the best combination of mixture ratio to the actual measurement, which is very similar to the average grain size distribution in the banking test area. Therefore, it is suggested that the overall geological characteristics as well as the grain size distribution should be considered in design stage to improve the soft ground that contains mixture of sand, silt, and clay.

• Journal of the Korean Geotechnical Society
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• v.26 no.11
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• pp.89-98
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• 2010

A method to design a critical height of embankments is presented so as to mobilize fully soil arching in pile-supported embankments. The behavior of the load transfer of embankment weights on pile cap beams was investigated by a series of model tests performed on pile-supported embankments with relatively wide space between cap beams. The model tests explained that the behavior of the load transfer depended very much on the height of embankments, because soil arching could be mobilized in pile-supported embankments only under enough high embankments. The measured vertical loads on cap beams coincided with the predicted ones estimated by the theoretical equations, which have been presented in the previous studies on the basis of load transfer mechanisms according to either the punching shear failure mode during low filling stage or the soil arching failure mode during high filling stage. The mechanism of the load transfer was shifted beyond a critical height of embankment from the punching shear mechanism to the soil arching mechanism. Therefore, in order to mobilize soil arching in pile-supported embankments, the embankments should be designed at least higher than the critical height. A theoretical equation to estimate the critical height could be derived by equalizing the vertical loads estimated by the load transfer mechanisms on the basis of both the punching shear and the soil arching. The derived theoretical equation could predict very well the experimental critical height of embankment.

• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.13-21
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• 2008

Partitioning tracer method is a useful tool to characterize large domains of the aquifers contaminated with light nonaqueous phase liquids (LNAPLs). Sorption of the partitioning tracers to the organic matter content of soil can potentially influence the efficacy of partitioning tracer method. LNAPL-water partitioning coefficients of tracers ($K_{nw}$), measured by static method, showed linear relationship. Sorption isotherm tests were conducted to evaluate the sorption capacity of the soils packed in the columns and the results were appropriately represented by Freundlich sorption isotherm. The sorption of tracers proportionally increased with the increase of the organic matter content of the soil. Laboratory experiments were conducted in four columns each packed with soils of different organic matter contents to determine the potential interference effects of sorption to soil organic matter content and correction factors for the errors in estimation of LNAPLs by partitioning tracer method. Though there were no contaminants added, breakthrough curves from columns packed with mixture of Jumunjin standard sand and organic matter showed separation of tracers. Columns were then contaminated to residual saturation with kerosene and breakthrough curves were obtained. The results show that sorption of tracers to soil organic matter leads to an increase in the retardation factor (R) and hence, to an overestimation of the saturation of LNAPLs. A relation between the percentage of organic matter content and the corresponding percentage error in the estimation of NAPLs has been developed.

• Composites Research
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• v.21 no.5
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• pp.9-14
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• 2008

Carbon nanofibers (CNFs) were used as dielectric lossy materials and NiFe particles were used as magnetic lossy materials. Total twelve specimens for the three types such as dielectric, magnetic and mixed radar absorbing materials (RAMs) were fabricated. Their complex permittivities and permeabilities in the range of $2{\sim}18$ GHz were measured using the transmission line technique. The parametric studios for reflection loss characteristics of each specimen to design the single-layered RAMs were performed. The mixed RAMs generally showed the improved absorbing characteristics with thinner matching thickness. One of the mixed RAMs, MD3with the thickness of 2.00 mm had the 10 dB absorbing bandwidth of 4.0 GHz in the X-band ($8.2{\sim}12.4$ GHz). It also showed very broad 10 dB absorbing bandwidth as wide as 6.0 GHz in the Ku-band ($12.0{\sim}18.0$ GHz) with the thickness tuning to 1.49 mm. The experimental results for selected several specimens were in very good agreements with simulation ones in terms of the overall reflection loss characteristics and 10 dB absorbing bandwidth.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.76-83
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• 2022

We attempted to estimate potential habitats of Clithon retropictus and to determine the community structure of benthic macroinvertebrates by presence of C. retropictus. 2016 to 2018 database of "Survey and Assessment of Estuary Ecosystem Health" by the Ministry of Environment were used to identify the distribution site of C. retropictus. The occupancy model was applied to estimate the potential habitat of C. retropictus. Four diversity indices were used to confirm the community structure of benthic macroinvertebrates. C. retropictus was found in the southern coast area and part of the east coast, and this pattern was consistent with previous studies. Additionally, the occupancy model predicted that a potential habitat of C. retropictus could appear in the west coast area. The community structure of benthic macroinvertebrates was relatively high at the site with C. retropictus than the site without C. retropictus. Therefore, the occupancy model can be considered when conserving C. retropictus inhabiting a limited area. Additionally, C. retropictus can be used to the indicator species that can represent the brackish water environment.

• Design Convergence Study
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• v.14 no.4
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• pp.181-192
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• 2015

The layout includes various functions not only arrangement, connection, division of information but also affordance and information recognition as the important element that determine the whole structure of information. Recently, the layout of web interface design was gradually changing from the concept of the original Z-layout to F-layout, whereas, it is being changed again into the split layout as the transform of Z-layout. However, there can be lack of grounds as to the reason of the change of layout. Therefore, it needs to study on how the functional difference between the F-layout and Z-layout affects user experience. In this study, we conduct the study on the effect of each layout type on the user experience focusing on the product description of web-page by user test. The user test have shown that the user has better feeling on the split layout based on the Z-layout than F-layout. The Z-layout also has more advantages on the formation of the favorable attitude of user in efficiency, accessibility and concentration. This result is consistent with the trend of web-design to change into the split layout based on the Z-layout and we provided the objective reasons for the effective web-design layout by user test.

• Ecology and Resilient Infrastructure
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• v.10 no.2
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• pp.31-39
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• 2023

NNbF is a newly emerging approach to reduce flood risk in coastal and fluvial areas using natural features or engineered nature-based features with the expectation of co-benefits of provisional, regulating, and socio-cultural services provided by the ecosystem. NNbF is not quite different from existing, related terms based on nature, such as NbS, Eco-DRR, NI, GI, EwN, and BwN, for all these terms include expectation of benefits for human societies by directly utilizing or mimicking nature's ecological functions. If we focus on the comprehensiveness of each term's subject and object, we can say that NbS > NNbF > (Eco-DRR, NI/GI). Among the 18 measures introduced in the NNbF International Guideline in the river and floodplain management category, it was found that measures of wash lands and floodplain restoration, including levee setback/removal and side-channel restoration, seemed to be the most applicable to rivers in Korea. These selected measures could be more effective when river managers purchase riparian lands along river courses by relevant laws for river water-quality protection.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.131-146
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• 2023

Smart card data is widely used in the public transportation field. Despite the inevitability of various errors occur during the data collection and storage; however, smart card data errors have not been extensively studied. This paper investigates inherent errors in boarding and alighting station information in smart card data. A comparison smart card data and bus boarding and alighting survey data for the same time frame shows that boarding station names differ by 6.2% between the two data sets. This indicates that the error rate of smart card data is 6.2% in terms of boarding station information, given that bus boarding and alighting survey data can be considered as ground truth. This paper propose 6-step algorithm for correcting errors in smart card boarding station information, linking them to corresponding information in Bus Information System(BIS) Data. Comparing BIS data and bus boarding and alighting survey data for the same time frame reveals that boarding station names correspond by 98.3% between the two data sets, indicating that BIS data can be used as reliable reference for ground truth. To evaluate its performance, applying the 6-step algorithm proposed in this paper to smart card data set shows that the error rate of boarding station information is reduced from 6.2% to 1.0%, resulting in a 5.2%p improvement in the accuracy of smart card data. It is expected that the proposed algorithm will enhance the process of adjusting bus routes and making decisions related to public transportation infrastructure investments.

• Journal of the Korean earth science society
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• v.44 no.3
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• pp.236-252
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• 2023

Both Earth science II and Korean geography textbooks emphasize the importance of content related to 'geology of the Korean Peninsula'. This study aimed to analyze the differences in the content related to the 'geology of the Korean Peninsula' presented in the textbooks, and to find out whether these differences are consistent with the latest scientific knowledge in any inconsistencies are found. For this purpose, seven textbooks (four Earth science II and three Korean geography) published under the 2015 revised curriculum were selected as the subject of analysis, and the difference in the description of the tectonic provinces of the Korean Peninsula, geologic time scale, and explanatory texts of geological characteristics between Earth science II and Korean geography textbooks were compared. As a result of the analysis, there are some cases of inconsistencies between Earth science II and Korean geography textbooks in terms of terminologies, names, and distribution ranges related to the tectonic provinces of the Korean Peninsula. The Korean geography textbooks had inconsistencies in the geochronologic data of the rocks as they cited outdated data. In addition, inconsistencies were found in the explanatory texts describing the 'distribution of rocks on the Korean Peninsula', 'characteristics of the Pyeongan Supergroup', and 'great hiatus of the Paleozoic Era'. Both Earth science and Geography have many concepts in common, therefore, effort is needed to minimize the differences in content. It is important to select the content appropriately which should reflect the latest scientific knowledge and presents the concepts consistently.