• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.05a
• /
• pp.359-360
• /
• 2021

The pixel-based processing of an image refers to a process of converting a value of one pixel only depending on the value of the current pixel, regardless of the value of another pixel. Pixel-based processing is used as the most basic operation in many fields such as image conversion, image enhancement, and image synthesis. There are processing methods such as arithmetic operation, histogram smoothing, and contrast stretching. In this paper, in order to clearly distinguish the tidal flat region from the tidal flat image of the west coast taken with a drone, we seek a method to find an efficient outline using pixel-based processing in the boundary detection part of the pre-processing process.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.45 no.1
• /
• pp.117-126
• /
• 2017

This study was carried out to figure out on the changes of longitudinal salt movement in the soil through the soil according to the materials and thickness of salt prevent materials and the place of salt prevent at reclaimed land from the sea which is one of the most serious problems when tree planting. Changes of soil salinity were different depending on the seasons. In particular, the soil salinity was lower during the rainy season. But during the dry seasons including early summer before the rainy season and winter season, salinity was relatively higher. Among the seven interruption materials, crushed stone, dredged sand and wood chips showed better interruption effects than the other materials. The interruption effect of salt movement was highest in the both of side and bottom interruption treatment of salt movement than the side interruption treatment of salt movement or the bottom interruption treatment of salt movement. The thickness of the layer should be at least 20cm to prevent salinity effectively.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1B
• /
• pp.161-168
• /
• 2008

The ecological environmental zones in coastal area, like tidal flat and salt marsh, were gradually decreased due to large scale of coastal development projects, reclamation and so on. Therefore, the development of artificial tidal flat and salt marsh has been emphasized in coastal area as mitigation concept and studies on related this background has performed. But studies on the quantitative evaluation for degree of restoration were insufficient. In this paper, as a fundamental study for evaluation of restoration on the creation of ecological environmental zones in coastal area, it was conducted that the monitoring and experiment for bio-chemical factors (bio-diversity, population and biomass of macro-benthos, survival ratio of reed, the number of heterotrophic bacteria and physico-chemical characteristics such as COD, IL, TN, TP and pH) using a in-situ pilot plant of tidal flat (Zone. P1) and salt marsh (Zone. P2), which was distinguished by content of dredged soil, in Jinudo, Nakdong estuary. From results of this study, the restoration index (RI), for evaluation concerning degree of restoration on the creation of ecological environmental zones in coastal area, was suggested and quantitative evaluation was performed using a restoration index (RI).

• Geophysics and Geophysical Exploration
• /
• v.13 no.4
• /
• pp.357-363
• /
• 2010

In this study, we investigated the geologic structure of the basement and overlying sediments of the construction site of the dinosaur egg fossil museum in Hwasung, Gyeonggi Province through refraction seismology, drilling, and downward seismic velocity measurements in the drill holes. The construction site ($350{\times}750\;m^2$) is located in the reclaimed area south of Sihwa Lake, Gojeong-ri. About 6,950 m of seismic refraction data consisting of 11 lines were acquired using a sledge hammer source. Drilling to the basement was performed at five sites. Sediment samples from drilling were analysed for grain-size distribution and age dating. At two drill holes, seismic velocity was measured with depth using a hammer as a seismic source. The geological structure of the study area consists of, from top to bottom, a tidal flat layer (5 ~ 12 m thick), a weathered soil layer (2 ~ 8 m thick), and the basement. The basement is interpreted as Cretaceous sedimentary rocks that tend to be shallow eastward. The volume of the tidal flat sediments and weathered soil in the study area is estimated as $1.4{\times}10^6\;m^3$, weighing $3.5{\times}10^6$ tons. The rate of sea level rise since 8,000 yrs BP is estimated to be 0.1 ~ 0.15 cm/yr.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.4 s.71
• /
• pp.43-49
• /
• 2006

Detailed investigations were carried out on the stability of the dredged soil bed against wave actions, aimedat establishing the design method of artificial tidal flats using dredged soil. The soil was dredged at Nagoya port, Japan, and has a mean grain size of 0.013mm. Basic features of artificial dredged soil bed against wave actions were explained from a series of model experiments in a wave flume. The two types of section shapes were employed; one is a horizontal bed and the other is a sloped one. Changes of the bed profile, shear strength, grain size distribution and water content, according to the wave actions, were measured in detail. The cumulative effect of the wave actions, over about one week, was investigated. A dredged soil bed moves withthe wave actions with relatively small wave height. It should be especially. noted that the clay component is dissolved and flown out, away from the surface layer, and consequently the surface layer hardens, as if it is covered with sand. Wren the wave height is gradually increased, the bed is not liquefied and the shear strength of the dredged bed is increased by a wave-induced dissipation of pore pressures in the bed and a decrease of clay component by the wave-induced leakage.

• The Korean Journal of Malacology
• /
• v.32 no.3
• /
• pp.175-184
• /
• 2016

In this study, we transplanted Chinese (Liaoning Dandong) and Chungnam (Taean) manila clam seeds to Gochang tidal flats in Jeonbuk province, and compared growth, mortality, and condition indices from May 2015 to August 2016. Within 2 months after transplantation, clam mortality of Chungnam and Chinese origin were $6.9{\pm}4.3%$, $16.9{\pm}7.9{\sim}21.0{\pm}6.3%$, respectively. We supposed that higher mortality of Chinese manila clams might be due to higher stress and weakening of physiological functions by air-exposure and unavailability of food intake for 5 days harvesting, transportation, quarantine procedures. Unlike the local clam farmer's opinion based on their field experience, growth of Chungnam clams in shell length and total weight were a little better than Chinese without statistical significant difference (P > 0.05). Condition indices of Chinese clams showed declining tendency after reaching a peak in May 2014, and in June 2015, respectively. Meanwhile, Chungnam clams has reached its peak of condition indices in May 2014 and in April 2015, respectively. From this result, we supposed that there might be at least one month difference in reproduction between the Chinese and Chungnam manila clams during the first-transplanted year. Because the mortality of adult clam have sharply increased from June 2015 (due to high temperature, few rainfall and spawning) in Gochang tidal flat, it would be recommendable that farmers harvest the clams before June when its shell length are larger than 40 mm. In conclusion, we could directly compare the productivity of Chinese and Chungnam manila clam at Gochang tidal flats by field experiment, and these results are also meaningful to manila clam farmers.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.3
• /
• pp.227-237
• /
• 2012

This paper analyzes the current status, characteristics, and problems of coastal reclamation in Korea and suggests effective management approaches. Reclamation is concentrated from the West Sea to the South Sea. In the 1980s and 1990s, most projects were intended for agricultural use, whereas in recent years reclamation for industrial and harbour sites(e.g., ship-building) have been increasing. The continuous onslaught of reclamation and development projects threatens the coastal environment, especially tidal flats and fishing areas, and fishery production has been reduced in some areas. The largest tidal flats have been used for dumping sites of dredged coastal sediments, urban development projects, and industrial complex composition. Thus, it is necessary to assess current policy using top-down approaches after establishing appropriate directions and standards for coastal management. Both short-term development profits and long-term conservation should be considered when attempting to balance development and conservation. In addition, improvements of marine environmental impact assessment and in the legal system are necessary.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.9
• /
• pp.907-912
• /
• 2008

In order to reduce the availability of dissolved inorganic phosphorus in surface water, lakes, and estuaries, black shale and zero valent iron can be used as reacitve materials. Sorption of phosphate to sampled sediment, black shale, and zero valent iron was quantitatively evaluated in this research. Effect of coexistence of calcium was also tested, since coexisting ions can enhance the precipitation of phosphate. An empirical kinetic model with fast sorption(k$_t$), slow sorption(k$_s$), and precipitation(k$_p$) was well fitted to experiment data from this research. Langmuir and Freundlich sorption isotherms were also used to evaluated phosphate maximum sorption capacity. Calcium ions at 0, 1 and 5 mM affected the precipitation kinetic coefficient in empirical kinetic model but did not have impact on the maximum sorbed concentration.

• Journal of the Korean association of regional geographers
• /
• v.15 no.2
• /
• pp.179-191
• /
• 2009

This study analyzes and compares the geomorphic characteristics and environmental changes of coastal plains such as the Anju and Hamheung Plains located in the west and east coasts of North Korea, respectively, based on topographic maps of the 1910s and satellite images of the 2000s. The Anju Plain, so called by as Yeoldusamcheonribeol, can be divided into alluvial plains, coastal plains and erosional plains. The Hamheung Plain can be regarded as alluvial plains formed by Seongcheon-river. Approximately 84.98$km^2$ tidal flats have been reclaimed to farmlands and saltpans, and the most channels of medium and small rivers have been straightened at the Anju Plain during the last one hundred years. At the Hamheung Plain, on the other hands, approximately 3.40$km^2$ land has been increased by the advances of coastal line of the Seongcheon-river delta with a maximum of 800m, and channels of Seoseongcheon-river which showed anastomosing channels have been disappeared by reclamation. Gwang-po has been decreased by artificial reclamations and river sedimentary processes.

• Korean Journal of Environment and Ecology
• /
• v.15 no.1
• /
• pp.57-68
• /
• 2001

해안지역의 녹화 및 조경용으로 유용한 내염성 식물자원임과 동시에 서식지가 급격히 감소하고 있는 순기비나무를 대상으로 하여 생장특성과 번식방법을 규명하기 위한 연구를 수행하였던 바, 그 결과를 요약하면 다음과 같다. 1. 줄기의 생장형태는 포복줄기와 직립줄기가동시에 생장하고, 5개 주요 군락지에 직립줄기의 길이는 평균 46.6cm 이고, 포복경의 초대 길이는 7.6cm에 달하였다. 2. 종작발아율은 황적색의 무처리 종자와 $GA_3$처리 종자에서 71.0~72.3%로 가장 높았으나, 두 처리군사이에는 발아율의 차이가 없었다. 종피현화를 목적으로 한 황산처리는 오히려 종자의 발아를 억제하였다. 3. 종피 색깔이 황적생인 종자는 흑갈색 종자에 비해 평균 21.1%(13~30%)발아율이 높았다. 실득모율은 30% 미만으로 아주 낮았으나 흑갈색 종자에 비해 황적색 종가자 약 2배 높았다. 또한 $LD_{50}$은 황적색 종자가 흑갈색 종자보다 10~20일 짧았다. 4. 종피 색깔과 화학처리가 같은 조건에서 기건저장한 종자와 노천매장한 종자사이에는 발아율, 식득묘율, $LD_{50}$등의 차이가 없었다. 5. 기건저장한 황적색 종자가 바다모래에서 30.3%의 발아율과 10.1%의 실득모율을 나타냈으나, 갯벌흙에서는 전혀 발아되지 않았다. 6. 삽목번식의 경우 추삽에서 발근육은 녹지삽이 가장 높았고, 다음이 반지숙삽, 숙지삽의 순이었다. 발근율이 가장 높은 것은 NAA 200ppm+sucrose 2%를 처리한 녹지로서 96.7%의 발근율을 나타내었다. 발근수는 전반적으로발근율에 비례하는 경향이었다. 7. 하삽에서 NAA 200ppm+sucrose 2%를 처리한 녹지, 반숙지, 숙지의 토양별 발근율은 vermiculite+ perlite(1:1)와 마사토에서는 81.1~87.8%로 높았고, 모래와 해상에서 48.9~77.8%로 낮았다.