• The Korean Journal of Mycology
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• v.21 no.3
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• pp.235-245
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• 1993

The symbiotic properties of arbuscular mycorrhizal fungi(AMF) such as the absence and/or presence of symbiosis, spore density, and six factors of phycochemical properties of soil were investigated in the rhizosphere of seven sand dune plants and three control plants around Kum river. The infection of AMF was confirmed in all plants. Three genera, nine species of the AMF spores were identified in the sand dune; Ac. scrobiculata, G. aggregatum, G. convolutum, G. diaphanum, G. dimophicum, G. geosporum, G. vesiculiferum, G. tortuosum, S. pachycaulis. All of them were also found in the control, but S. pachycaulis were only separated in the sand dune. In the control, three genera, four species were identified; G. flavisporum, Gi. margarita, Sc. gregaria. Sc. persica. The species specificity was not found between the sand dune plant and AMF. However, the AMF was thought to be correlated with the soil factors. The spore density was stimulated with increase of the organic matter and the nitrogen content, but inhibited with the water content and the phosphorus content. In respect of the seasonal factor, the spore density was increased in the late growth period of plants.

• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.79-92
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• 2016

Samples from two boreholes of coastal dune field at Jangho-ri coast, Gochang was studied. These were analyzed by grain size analysis geochemical analysis, and the application of OSL dating method to understand the development during the Holocene. The boreholes SB8 and SB9 were classified into three different sedimentary layers by their mean grain size and geochemical characteristics. The results revealed that the upper sand layer is equivalent to the present coastal dune layer, which developed since 1,200 years ago; the silt layer in the middle to the dune slack or lagoon sedimentation layer, which developed between 1,200 and 6,000 years ago; and the sand layer at the bottom to the paleo coastal dune that developed between 6,000 and 7,000 years ago. It was proposed that the forming material of current coastal dune was supplied from the sandy flat in coastal area, while the middle silt layer was supplied from the weathered soil of a bed rock by the comparison with material of surrounding area. In the case of coastal dune, concentrated layer of sands were identified which were buried about 300 and 1,200 years ago, which is identified as the little ice age. This study confirmed the development of Jangho-ri coastal dunes after Holocene Climate Optimum period, and it is likely to assist in the understanding of coastal dunes development.

• Korean Journal of Environmental Biology
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• v.25 no.1
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• pp.56-65
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• 2007

The aim of this study is to provide a fundamental data which can be applied to management conservation, and restoration of coastal sand dune vegetation by determining the classification and distribution of community, and ecological characteristics of the habitat. This research was performed by the Braun-Blanquet's method. The coastal sand dune vegetation of Uido (I.) was composed with 9 communities as follows : Vitex rotundifolia community, Zoysia macrostachya community, Carex kobomugi community, Iachaemum anthephoroides community, Imperata cylindrica var. koenigii community, Carex pumila community, Calystegia soldanella community Messerschmidia sibirica community and Pinus thunbergii community, the evergreen needle-leaved forest. The constancy degree showed high in Calystegia soldanella (77%), Vitex rotundifolia (74%), Carex kobomugi (66%), Zoysia macrostachya (50%) and Imperata cylindrica var. koenigii (47%). However the highest constancy degree Calystegia soldanella has, it turned out to have low net contribution degree (NCD) in each community. In terms of the distribution and growth feature of the composition species in the coastal sand dune, Vitex rotundifolia, Carex kobomuri and Zoysia macrostachya were widely distributed from unstable sand dune to stable one but Iachaemum anthephoroides and Imperata cylindrica var. koenigii were mainly found at the stable sand dune. Carex kobomugi was especially dominant at the unstable sand dune where the sand continued to be deposited. On the other hand, Carer pumila and Messerschmidia sibirica showed regional distributions around fresh water.

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.380-388
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• 2017

Factors affecting spatial distribution of halophytes were analyzed in June 2012 at the Goraebul coastal dunes. In the Goraebul sand dune, distribution of halophytes was divided into three groups. The first group belonging to Elymus mollis, Carex kobomugi, Calystegia soldanella, Ixeris repens and Glehnia littoralis was distributed in the ridge of primary sand dune and dune slack. The second group belonging to Lathyrus japonicus and Zoysia macrostachya was distributed in the dune slack. The third group belonging to Pinus thunbergii, Vitex rotundifolia and Linaria japonicus was distributed in the pine forest of the secondary sand dune. E. mollis, C. kobomugi, C. soldanella, I. repens and G. littoralis was distributed in relatively unstable habitat of sand dunes due to the large amount of sand movement. V. rotundifolia was distributed in a relatively stable habitat. Factors that have the greatest influence on distribution of halophytes in the Goraebul sand dunes are distance from the seashore, topography, and the pine forest. The Goraebul sand dune is a relatively well-preserved area with minimal human intervention. Therefore, different distribution of physico-chemical factors by natural processes is essential to spatial distribution of halophytes than other sand dunes in Korea. Significant natural processes in the Goraebul sand dunes were advance and retreat of coastlines from waves, erosion and sedimentation of sand due to wind and waves, and dispersal of seawater.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.6
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• pp.25-33
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• 2022

In this study, a monitoring method using high-resolution images acquired by unmanned aerial vehicles and deep learning algorithms was proposed for the management of the Sinduri coastal sand dunes. Class classification was done using U-net, a semantic division method. The classification target classified 3 types of sand dune vegetation into 4 classes, and the model was trained and tested with a total of 320 training images and 48 test images. Ignored label was applied to improve the performance of the model, and then evaluated by applying two loss functions, CE Loss and BCE Loss. As a result of the evaluation, when CE Loss was applied, the value of mIoU for each class was the highest, but it can be judged that the performance of BCE Loss is better considering the time efficiency consumed in learning. It is meaningful as a pilot application of unmanned aerial vehicles and deep learning as a method to monitor and manage sand dune vegetation. The possibility of using the deep learning image analysis technology to monitor sand dune vegetation has been confirmed, and it is expected that the proposed method can be used not only in sand dune vegetation but also in various fields such as forests and grasslands.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.35-50
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• 2017

This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.2
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• pp.180-194
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• 2010

Coastal sand dunes are dynamic and fragile buffer zones of sand and vegetation where the following three characteristics can be found: large quantities of sand, persistent wind capable of moving sand, and suitable locations for sand to accumulate. The functional properties of coastal sand dunes include the roles in sand storage, underground freshwater storage, coastal defense, and ecological environment space, among others. Recently, however, the integrity of coastal dune systems has been threatened by development, including sand extraction for the construction industry, military usage, conversion to golf courses, the building of seawalls and breakwaters, and recreational facility development. In this paper, we examined the development mechanisms and structural/format types of coastal sand dunes, as well as their functions and value from the perspective of coastal engineering based on reviews of previous researches and a case study of a small coastal sand dune in the Nakdong river estuary. Existing data indicate that there are a total of 133 coastal sand dunes in South Korea, 43 distributed on the East Sea coast (32 in the Gangwon area, and 11 in Gyeongsangbuk-do), 60 on the West Sea coast (4 in Incheon and Gyeonggi-do, 42 in Ghungcheongnam-do, 9 in Jellabuk-do, and 5 in Jellanam-do), and 30 on the South Sea coast (16 in Jellanam-do, 2 in Gyeongsangnam-do, and 12 in Jeju).

• The Korean Journal of Quaternary Research
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• v.7 no.1
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• pp.93-101
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• 1993

A sedimentation study of the Cheonripo intertidal beach sands and its related coastal dune sands, Cheonripo, Seosan Gun, Choongcheong Namdo, Korea has been carried out based on a series of several summer time field surveys. Each subenvironment in the Cheonripo coastal zone, that is, intertidal sand beach and coastal sand dune, could be differenciated in terms of textural parameters. The coastal dune sands are finer than the intertidal beach sands in mean grain size, and the sorting of dune sands is relatively poorer than that of intertidal beach sands. However, the skewness of intertidal beach and dune sands is commonly positive. Such textural parameters are characteristically differentiated on scatter diagrams. A series of megaripple bedform observations for 6 tidal cycle periods(August 13, 14 and 15, 1990) are interpreted to find out migration pattern of bedforms and its related sand migration. Such migration natures are shown on the tables and figures.

• Advances in concrete construction
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• v.13 no.4
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• pp.315-325
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• 2022

Reinforced concrete structures are exposed throughout their lifetime to the phenomenon of carbonation, which considerably influences their durability by causing corrosion of the reinforcements. The fight against this phenomenon is usually ensured by anti-carbonation coatings which have the possibility of limiting the permeability to carbon dioxide or with coatings which absorb the CO₂ present in the air. A coating with good crack-bridging (sealing) capacity will prevent water from entering through existing cracks in concrete. Despite the beneficial effect of these coatings, their durability decreases considerably over time with temperature and humidity. In order to use coatings made from local materials, not presenting any danger, available in abundance in our country, very economical and easy to operate is the main objective of this work. This paper aim is to contribute to the formulation of a corrected dune sand-based mortar as an anti-carbonation coating for concrete. The results obtained show that the cement mortar based on dune sand formulated has a very satisfactory compressive strength, a very low water porosity compared to ordinary cement mortar and that this mortar allows an improvement in the protection of the concrete against the carbonation of 60% compared to ordinary cement mortar based on alluvial sand. Moreover, the formulated cement mortars based on dune sand have good adhesion to the concrete support, their adhesion strengths are greater than 1.5MPa recommended by the standards.

• Journal of computational fluids engineering
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• v.10 no.1
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• pp.31-38
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• 2005

Three-dimensional flow over the sand dunes have been studied numerically by using Large-Eddy Simulation (LES) method. In the direction of initial flow and span direction cyclic boundary conditions are imposed for velocity and pressure. The movement of the sand dune which is formed by converging wind direction has been investigated. The numerical method employed in this study can be divided into three parts: (i) calculation of the air flow over the sand dune using standard MAC method with a generalized coordinate system; (ii) estimation of the sand transfer caused by the flow through the friction; (iii) determination of the shape of the sand surface. Since the computational area has been changed due to step (iii), (i)-(iii) are repeated. The simulated dune, which has initially elliptic cross section, extends at the converging direction, which is known as linear dunes.