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Long-term Changes of Bathymetry and Surface Sediments in the dammed Yeongsan River Estuary, Korea, and Their Depositional Implication (영산강 하구의 수심 및 표층 퇴적물 특성의 변화와 퇴적환경)

  • KIM, YOUNG-GIL;CHANG, JIN HO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.22 no.3
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    • pp.88-102
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    • 2017
  • Long-term changes in bathymetry and grain size of surface sediments were investigated for understanding depositional sedimentary environments in the channelized Yeongsan River Estuary, Korea. The results revealed that an average depth of the estuary had decreased up to 2.1 m from 1982 to 2006, while it had increased to 0.3 m from 2006 to 2012. The rapid decrease of the water depth from 1982 to 2006 was due to the vast deposition of mud caused by the change of water course and flow velocity after the estuary was dammed. Meanwhile the increase of the water depth from 2006 to 2012 may be associated with multiple erosional processes, including a dredging at the southern part of the estuary and other erosions from the dike sluice expansion work. Considering the water-depth change and tidal-level variation in the study area, an depositional rate in the estuary is estimated to be 8~9 cm/yr for the last 2 decades (1982~2006). The sediments of Yeongsan River Estuary are largely composed of silt-clay mixtures: overall, silt is distributed mainly in the shallow area of the estuary edge, while clay is confined to the deep area of the estuary center. Mean grain size of the sediments is 6.0 Ø on average in 1997, 7.8 Ø on average in 2005 and 7.7 Ø on average in 2012, respectively, suggesting that the sediments became finer due to the increase of silt and clay contents in 1997~2005. Furthermore, several lines of evidences, including the comparison between the amounts of the sediment influx discharged from the Yeongsan River and the sediments in the estuary, and the changes in distribution pattern of silt and clay contents implying that they moved from offshore to estuary dike, indicate that the mud sediments are originated mainly from the offshore, not from the river.

Development of EvaGreen Based Real-time PCR Assay for Detection and Quantification Toxic Dinoflagellate Pfiesteria Piscicida and Field Applications (유독 와편모조류 Pfiesteria Piscicida 탐지 및 정량 분석을 위한 EvaGreen 기반 Real-time PCR기법 개발과 현장 적용)

  • PARK, BUM SOO;JOO, JAE-HYOUNG;KIM, MYO-KYUNG;KIM, JOO-HWAN;KIM, JIN HO;BAEK, SEUNG HO;HAN, MYUNG-SOO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.22 no.1
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    • pp.31-44
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    • 2017
  • Pfiesteria piscicida is one of heterotrophic dinoflagellate having toxic metaboliges, and it is difficult to detect and quantify this dinoflagellate via light microscope due to small size and morphological similarity with Pfiesteria-like dinoflagellate (PLD) species. Alternatively, we developed quantitative real-time PCR assay based on EvaGreen and determined field accessibility throughout the investigation of distribution in the entire Korean coastal waters and population dynamics in Shihwa Lake. The P. piscicida-specific primers based on internal transcribed spacer 1 (ITS 1) were designed and the specificity of primers was confirmed by PCR with other genomic DNAs which have genetic similarity with target species. Through real-time PCR assay, a standard curve which had a significant linear correlation between log cell number and $C_T$ value ($r^2{\geq}0.999$) and one informative melting peak ($88^{\circ}C$) were obtained. These results implies that developed real-time PCR can accurately detect and quantify P. piscicida. Throughout the field applications of real-time PCR assay, P. piscicida was distributed in western (Mokpo and Kimje) and easthern (Gangneng) Korean coastal water even though light microscopy failed to identify P. piscicida. In the investigation of population dynamics in Shihwa Lake, the density of P. piscicida was peaked in June, July and August 2007 at St. 1 where salinity (${\leq}15psu$) was lower than the other 2 sites. In this study, we successed to develop EvaGreen bassed real-time PCR for detection and quantification of P. piscicida in fields, so this developed assay will be useful for various ecological studies in the future.

Changes in Biochemical Components of Several Tissues in Solen grandis, in Relation to Gonad Developmental Phases (대맛조개, Solen grandis의 생식소 발달 단계에 따른 일부 조직의 생화학적 성분변화)

  • Chung, Ee-Yung;Kim, Hyun-Jin;Kim, Jong-Bae;Lee, Chang-Hoon
    • The Korean Journal of Malacology
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    • v.22 no.1 s.35
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    • pp.27-38
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    • 2006
  • We investigated the reproductive cycle with gonad developmental phases of Solen grandis by histological observations. Seasonal changes in biochemical components of the adductor muscle, visceral mass, foot muscle and mantle were studied by biochemical analysis, from January to December, 2005. The reproductive cycle of this species can be classified into five successive stages: early active stage (December to January), late active stage (January to March), ripe stage (March to July), partially spawned stage (June to July) and spent/inactive stage (July to December). Total protein content was the highest in the foot muscle, the content was high in January (early active stage), the lowest in April (ripe stage), and was the highest in August (partially spawned stage). In the visceral mass, total protein content began to increase in February (late active stage) and reached a maximum in March (ripe stage). Thereafter, it gradually decreased between June and July (partially spawned stage). There was a strong negative correlation in total protein contents between visceral mass and mantle (r = -0.594, p = 0.042). Meanwhile there was a positive correlation between the adductor muscle and foot muscle, the correlation was not statistically significant (r = 0.507, p = 0.093). Total lipid content was the highest in the visceral mass; it was more than 2 to 5-fold higher than that in the adductor muscle, foot muscle, and mantle. Monthly changes in total lipid content were also most dynamic in the visceral mass. It was relatively higher between January and February, showed a maximum in March (the ripe stage), decreased rapidly from April to July (ripe and partially spawned stage), and gradually decreased from September to December (spent/inactive stage). There was a strong positive correlation in total lipid content between foot muscle and adductor muscle (r = 0.639, p = 0.025). Tthough a negative correlation was found between visceral mass and mantle (r = -0.392), the correlation was not statistically significant (p = 0.208). Glycogen contents changed within relatively narrow range and were similar among different tissues. There was no statistically significant correlation in glycogen contents among tissues.

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Neotectonic Crustal Deformation and Current Stress Field in the Korean Peninsula and Their Tectonic Implications: A Review (한반도 신기 지각변형과 현생 응력장 그리고 지구조적 의미: 논평)

  • Kim, Min-Cheol;Jung, Soohwan;Yoon, Sangwon;Jeong, Rae-Yoon;Song, Cheol Woo;Son, Moon
    • The Journal of the Petrological Society of Korea
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    • v.25 no.3
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    • pp.169-193
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    • 2016
  • In order to characterize the Neotectonic crustal deformation and current stress field in and around the Korean Peninsula and to interpret their tectonic implications, this paper synthetically analyzes the previous Quaternary fault and focal mechanism solution data and recent geotechnical in-situ stress data and examines the characteristics of crustal deformations and tectonic settings in and around East Asia after the Miocene. Most of the Quaternary fault outcrops in SE Korea occur along major inherited fault zones and show a NS-striking top-to-the-west thrust geometry, indicating that the faults were produced by local reactivation of appropriately oriented preexisting weaknesses under EW-trending pure compressional stress field. The focal mechanism solutions in and around the Korean Peninsula disclose that strike-slip faulting containing some reverse-slip component and reverse-slip faulting are significantly dominant on land and in sea area, respectively. The P-axes are horizontally clustered in ENE-WSW direction, whereas the T-axes are girdle-distributed in NNW direction. The geotechnical in-situ stress data in South Korea also indicate the ENE-trending maximum horizontal stress. The current crustal deformation in the Korean Peninsula is thus characterized by crustal contraction under regional ENE-WSW or E-W compression stress field. Based on the regional stress trajectories in and around East Asia, the current stress regime is interpreted to have resulted from the cooperation of westward shallow subduction of the Pacific Plate and collision of Indian and Eurasian continents, whereas the Philippine Sea plate have not a decisive effect on the stress-regime in the Korean Peninsula due to its high-angle subduction that resulted in dominant crust extension of the back-arc region. It is also interpreted that the Neotectonic crustal deformation and present-day tectonic setting of East Asia commenced with the change of the Pacific Plate motion during 5~3.2 Ma.

A Study on the Buddhist Stone Arts of Mt. Bukhan (북한산 불교 석조미술 연구)

  • Lee, Seohyun
    • Korean Journal of Heritage: History & Science
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    • v.52 no.1
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    • pp.90-119
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    • 2019
  • The purpose of this study is to investigate the significance of Buddhist stone art in the cultural zone of Mt. Bukhan. Mt. Bukhan witnessed the prevalence of Buddhist culture in and around it since the introduction of Korean Buddhism and served as the center of Buddhist culture in the nation, where new Buddhist temples continued to be built from the Three Kingdoms Period to the Joseon Period. Of the characteristics of its Buddhist culture, it is very noteworthy that the construction of military temples in and around it in the latter half of Joseon supported the function of Buddhist temples as basic places of worship. These military temples were closely related to the mountain's geopolitical location, traffic routes, and position in the national defense system-- its mountain fortress was an important defense facility. The stone art works of Mt. Bukhan can be categorized into various types, including stone stupas, stone pagodas, rock-carved Buddhas, stone Buddhas, towers and monuments (stone monuments), stone lanterns, flagpole supports, and rock-carved sarira pagodas. There are diverse types of stone art left on the mountain. As for its period characteristics, it is clear that the Buddhist art of Silla spread even to the Gyeonggi region, and that most of the works of stone art were created during the first half of Goryeo and the latter half of Joseon. Starting in Goryeo, the Buddhist temples of the mountain maintained close relations with the royal court by operating as the royal buddhist shrine for the royal family. In the latter part of Joseon, the construction of the Bukhan mountain fortress became the most important opportunity to produce stone art. As for the distribution of the stone artwork, it was usually created in the west part of the mountain from Unified Silla to the first half of Goryeo and in the southern and eastern parts of the mountain from the latter half of Goryeo to the latter half of Joseon. It is estimated that central Buddhist temples of the mountain changed due to Silla's military goal of advancing toward the west coast along the Han River in its early days and the construction of the Bukhan mountain fortress in the latter half of Joseon to protect the capital city. Finally, the stone art of Mt. Bukhan holds very high significance in art history because various types of stone art continued to be created on and around the mountain, the stone artwork of the mountain reflected representative styles for each period, and e rare and ofthe works produced on the mountain exemplified rare and unique styles.

The Ecological Values of the Korean Demilitarized Zone(DMZ) and International Natural Protected Areas (비무장지대(DMZ)의 생태적 가치와 국제자연보호지역)

  • Cho, Do-soon
    • Korean Journal of Heritage: History & Science
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    • v.52 no.1
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    • pp.272-287
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    • 2019
  • The Korean Demilitarized Zone (DMZ) was established in 1953 by the Korean War Armistice Agreement. It extends from the estuary of the Imjin River, in the west, to the coast of the East Sea. It is 4 km in width and 148 km in length. However, the ecosystems of the civilian control zone (CCZ) located between the southern border of the DMZ and the civilian control line (CCL) and the CCZ in the estuary of the Han River and the Yellow Sea are similar to those in the DMZ, and, therefore, the ecosystems of the DMZ and the CCZ are collectively known as the "ecosystems of the DMZ and its vicinities." The flora in the DMZ and its vicinities is composed of 1,864 species, which accounts for about 42% of all the vascular plant species on the Korean Peninsula and its affiliated islands. Conducting a detailed survey on the vegetation, flora, and fauna in the DMZ is almost impossible due to the presence of landmines and limitations on the time allowed to be spent in the DMZ. However, to assess the environmental impact of the Munsan-Gaesong railroad reconstruction project, it was possible to undertake a limited vegetation survey within the DMZ in 2001. The vegetation in Jangdan-myeon, in Paju City within the DMZ, was very simple. It was mostly secondary forests dominated by oaks such as Quercus mongolica, Q. acutissima, and Q. variabilis. The other half of the DMZ in Jangdan-myeon was occupied by grassland composed of tall grasses such as Miscanthus sinensis, M. sacchariflorus, and Phragmites japonica. Contrary to the expectation that the DMZ may be covered with pristine mature forests due to more than 60 years of no human interference, the vegetation in the DMZ was composed of simple secondary forests and grasslands formed on former rice paddies and agricultural fields. At present, the only legal protection system planned for the DMZ is the Natural Environment Conservation Act, which ensures that the DMZ would be managed as a nature reserve for only two years following Korean reunification. Therefore, firstly, the DMZ should be designated as a site of domestic legally protected areas such as nature reserve (natural monument), scenic site, national park, etc. In addition, we need to try to designate the DMZ as a UNESCO Biosphere Reserve or as a World Heritage site, or as a Ramsar international wetland for international cooperation. For nomination as a world heritage site, we can emphasize the ecological and landscape value of the wetlands converted from the former rice paddies and the secondary forests maintained by frequent fires initiated by military activities. If the two Koreas unexpectedly reunite without any measures in place for the protection of nature in the DMZ, the conditions prior to the Korean War, such as rice paddies and villages, will return. In order to maintain the current condition of the ecosystems in the DMZ, we have to discuss and prepare for measures including the retention of mines and barbed-wire fences, the construction of roads and railroads in the form of tunnels or bridges, and the maintenance of the current fire regime in the DMZ.

An Experimental and Numerical Study on the Survivability of a Long Pipe-Type Buoy Structure in Waves (긴 파이프로 이뤄진 세장형 부이 구조물의 파랑 중 생존성에 관한 모형시험 및 수치해석 연구)

  • Kwon, Yong-Ju;Nam, Bo-Woo;Kim, Nam-Woo;Park, In-Bo;Kim, Sea-Moon
    • Journal of Navigation and Port Research
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    • v.42 no.6
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    • pp.427-436
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    • 2018
  • In this study, experimental and numerical analysis were performed on the survivability of a long pipe-type buoy structure in waves. The buoy structure is an articulated tower consisting of an upper structure, buoyancy module, and gravity anchor with long pipes forming the base frame. A series of experiment were performed in the ocean engineering basin of KRISO with the scaled model of 1/ 22 to evaluate the survivability of the buoy structure at West Sea in South Korea. Survival condition was considered as the wave of 50 year return period. Additional experiments were performed to investigate the effects of current and wave period. The factors considered for the evaluation of the buoy's survival were the pitch angle of the structure, anchor reaction force, and the number of submergence of the upper structure. Numerical simulations were carried out with the OrcaFlex, the commercial program for the mooring analysis, with the aim of performing mutual validation with the experimental results. Based on the evaluation, the behavior characteristics of the buoy structure were first examined according to the tidal conditions. The changes were investigated for the pitch angle and anchor reaction force at HAT and LAT conditions, and the results directly compared with those obtained from numerical simulation. Secondly, the response characteristics of the buoy structure were studied depending on the wave period and the presence of current velocity. Third, the number of submergence through video analysis was compared with the simulation results in relation to the submergence of the upper structure. Finally, the simulation results for structural responses which were not directly measured in the experiment were presented, and the structural safety discussed in the survival waves. Through a series of survivability evaluation studies, the behavior characteristics of the buoy structure were examined in survival waves. The vulnerability and utility of the buoy structure were investigated through the sensitivity studies of waves, current, and tides.

Kui-Myeong-kui as sprauchlement of Pungmul-Kut - especially in Jeollanambuk-do (풍물굿으로서의 기명기와 그 접변현상 - 전라남북도를 중심으로)

  • Park, Heung-Ju
    • (The) Research of the performance art and culture
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    • no.32
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    • pp.131-169
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    • 2016
  • We will study cultural sprauchling about Pungmul-Kut to find out the sphere of "Gui-myeong-gui" alongside Jeollanam-do, Jeollabuk-do western coast. In this area, there are some traits and terms about Gui-myeong-gui, a sort of Pungmul-Kut and Goon-go. Several Pungmul-Kuts which border the sphere of Gui-myeong-gui are Goon-gui in a southern direction, Unnyeongnongak of Honamudonongak in a eartern direction, and Yeongmujangnongak. The acculturation occurs in two ways. One is the possible acculturation with Goon-gi or Goon-go in coastal areas. The other is the acculturation with Honamudonongak. Especially, this phenomenan appears in double-way interaction. At first, there is the influence of Gui-myeong-gui in Honamudonongak. Kim Bau's style, which might relate to Gui-myeong-gui in Geommopojin, incorporate one of Panje of Honamudonongak through Park Namsik. This phenomenon is porved by the affinity between Eunjijaetji Galag of Honamudonongak GeollibKut and Eungmagaenggaeng Galag of Goon-go, and by the similarity to Neonari-Galag. In case of Neonari-Galag, the role of Jing in Neonari-Galag is replaced by Janggu in Honamudonongak, because of the geatest popularity of Janggu in those days. Secondly, there is the influence of Honamudonongak in Gui-myeong-gui. Northern sphere of Gui-myeong-gui like Buan-gun, Okgu-gun has been influenced since early $20^{th}$ century. In addition, the phenomenon which the sphere of Gui-myeong-gui accepts actively Honamudonongak could occur. So this thesis fragmentarilly checks the existence and traits of Gui-myeong-gui. Based on it, we would be able to reveal and reconstitute the nature of Gui-myeong-gui by understanding acculturation of Pungmul-Kut and by comparing Goon-go with Honamudonongak and Yeongmujangnongak in several regions. Also this thesis draws attention about meanings and effects of Yeonhuinongak's acceptace of Goon-beop.

A Reexamination of the Impact of the Fit of Corporate Social Responsibility on the Brand Attitude: The Perspective of Brand Hierarchy (기업의 사회적 책임(CSR)활동의적합성이 브랜드 태도에 미치는 영향에 관한 재고찰: 브랜드 계층구조 관점에서)

  • YANG, JAEHO;Seo, Hae-Jin;Song, Tae-Ho
    • (The) Korean Journal of Advertising
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    • v.27 no.8
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    • pp.59-90
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    • 2016
  • Consumers demand that corporates fulfill their social responsibility by exerting influence over not only economical values but also social values in markets. Given such a social mood, most corporates are actively engaging in Corporate Social Responsibility(CSR) activities, and marketing scholars continue to study the effects of such CSR activities. Numerous such studies examined the relationship between CSR activity and brand equity. Moreover, virtually, a majority of these studies focused on consumer responses to CSR activity from an individual brand perspective. In a situation in which brand management must consider the spillover effects of brands, firms holding various brands should consider these spillover effects when they establish CSR activity strategies. Therefore, we examine the effects of CSR activity using a comprehensive approach that considers the hierarchy of brands. Additionally, we develop a new perspective on fit that has been used as a major influence on the effects of CSR activity. We argue that the mixed results of the impact of fit regarding the effect of CSR activities is attributed to the influence of connections among brands based on the hierarchy of brands. We then examine the effect of two types of CSR activity strategies that reflect the relativity of fit. The results reveal that there was no difference in impact of the two strategies based on unique roles and traits of corporate brand and effects of low fit. Also, we found that the corporate brand focused strategy creates a greater change in consumers' attitudes than does an individual brand focused strategy in the case of a particular brand. This finding is meaningful because it indicates that a hierarchy of brands may relatively reduce the impact of the role of fit, unlike general arguments from previous related research. Second, the spillover effects from the CSR activities of individual sub-brands belonging to the same corporate brand were confirmed. Therefore, we clearly verified the role of the hierarchy of brands. Although both strategies cause changes in consumer attitude toward brands engaged in CSR activity, overall, a corporate brand focused strategy turned out to be more effective than an individual brand focused strategy because of the spillover effects of brands. Third, this study verified the effect of a corporate brand focused strategy through a moderating effect analysis of the degree of association between individual brands and corporate brand. Given these results, we identified a moderating role in the degree of association and the changes in consumer attitudes toward both main brands engaged in CSR activities and other different individual brands, which were caused by the spillover effects of brands. Finally, this study addresses implications and limitations.

Growth and Blood Characteristics of Red Sea Bream Pagrus major by Starvation and Stocking Density during Red Tide (적조발생시기 참돔의 절식과 사육밀도에 따른 성장과 혈액성상)

  • Kim, Won-Jin;Lee, Jeong-Yong;Shin, Yun-Kyung;Won, Kyoung-Mi
    • Korean Journal of Ichthyology
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    • v.30 no.4
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    • pp.194-204
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    • 2018
  • In order to minimize the damage on the red sea bream Pagrus major by a harmful dinoflagellate Cochlodinium polykrikoides, we investigated the effect of feeding, starvation and stocking density on the survival rate, growth, growth restoration and physiological response of P. major exposure to C. polykrikoides. The experimental groups were divided into three groups such as F-HD (feeding and high density with $6.4kg/m^3$), S-HD (starvation and high density with $6.4kg/m^3$) and S-LD (starvation and low density with $3.2kg/m^3$) according to stocking density and starvation in marine cage ($11m{\times}11m{\times}5m$). The F-HD was fed throughout the experiment for 9 weeks, whereas S-HD and S-LD were not fed for 5 weeks and then refeeding for 4 weeks. Survival rate was the lowest in F-HD (85.5%) and S-LD was the highest (97.3%). The growth rates of S-HD and S-LD were significantly lower than F-HD during starvation period for 4 weeks, but rapidly recovered after feeding. The nutritional status such as ALB, TP, TCH, TG were similar to tendency of growth data. Ht, Hb, AST, ALT and GLU levels were significantly higher in the F-HD than in the starvation groups at the same time (in 3 week) during starvation period. But starvation groups did not differ during starvation period. As a result, F-HD is more sensitive to stress than S-HD and S-LD. Thus, during C. polykrikoides bloom period, starvation and stocking density control can help survival and growth restoration of the red sea bream.