• 한국지형학회지
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• 제26권4호
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• pp.33-45
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• 2019

The shore platforms at Dok-do could be an important and clear indicator showing dimensional reduction of Dok-do. Especially flat type shore platforms are distributed in the southern coast of Dok-do island, composed of weak rocks against erosional resistance like interbedded lapilli tuff and massive tuff breccia. The distribution of shore platform is partially related to the wind direction at Dok-do island. The primary SW- and secondary SE winds are representative among wind directions at Dok-do, maintaining from spring to the autumn. Therefore, wide shore platforms could be developed by waves approaching from SW and SE directions in the southern coast of Dok-do. The sea stacks like Gunham-rock, Neopdeok-rock, Keungaje-rock and Jakeungaje-rock on the western coast are also considered to be formed by wave erosion from the SE direction. The shore platforms in the southern coast of Dok-do island were developed since ca. 7,000 yr. BP, when sea level raised almost to the present level. The average extension speed of shore platform was calculated to 4.0mm/y, because the broadest shore platform with the width ca. 28m was extended for ca. 7,000 years. The width's dimension of shore platform at Dok-do reflects a slow extension rate in the present, although erosional process will be faster with the sea level rise in the future.

• 한국지역지리학회지
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• 제13권1호
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• pp.32-42
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• 2007

제주도 남서부 안덕면의 사계해안에는 미고결 하모리층의 파식대지와 해안단구 퇴적층, 패사 및 화산사로 이루어진 해안사구, 배후호소 등이 상호 유기적으로 연계되어 있다. 본 연구에서 OSL 연대측정법을 이용하여 분석한 사계 해안지형시스템의 형성과정은 다음과 같다. 첫째, 하모리층은 약 7,600$\sim$3,000년 전에 해저 화산분출에 의하여 재 이동된 응회암이 쌓인 수평 지층이다. 하모리층과 광해악현무암의 완사면이 만나는 부분에 형성된 와지는 이후 지반이 융기하여 육상으로 드러나면 배후호소를 이룬다. 둘째, 하모리층이 아직 해수면 아래에 있을 때, 광해악현무암으로 이루어진 남서부의 암석해안에서 부서져 마모된 것이거나 소하천으로 공급된 자갈들이 빠른 유수를 따라 이동하여 퇴적되었다. 셋째, 이후 지반이 융기함으로써 원력의 퇴적은 중단되었으며, 파랑의 전진에너지에 따른 마식작용으로 파식대가 형성되었다. 파식대의 고도는 대조시의 고조위면과 일치하므로, 현재 연구지역의 고조위면과 비교해 보면, 지반은 파식대 형성 이후 약 1.5m 융기하였다. 넷째, 해저로부터 많은 사질 퇴적물이 공급되어 파식대지와 해안단구 역층을 피복하였다. 사질 퇴적물 가운데 보다 가벼운 입자들은 바람에 실려 배후로 이동하여 500년 전부터 전사구나 이차사구를 형성하였다.

• 한국수산과학회지
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• 제46권2호
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• pp.176-185
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• 2013

Seasonal species composition and biomass of microphytobenthos were examined at the intertidal flats of Jinsanri, Taean, Korea, from April to December 2011. In total, 121 species were identified, including 109 diatoms, 5 blue-green algae, and 5 dinoflagellates. Seasonal variation in species number ranged from 49 to 56 species (minimum in October and maximal in April), while vertical variation across three different shore levels ranged from 64 to 77 species with maximum at high and minimum at low shore. Species diversity ranged from 3.22 to 3.42 seasonally and from 3.50 to 3.17 across vertical shore levels. Seasonal average values of the normalized difference vegetation index and the vegetation index were 0.06 and 1.14, respectively. Chlorophyll a concentrations were $66.00-120.73mg/m^2$, with a seasonal minimum and maximum in July and October, respectively, and a vertical shore maximum of $137.35mg/m^2$ at mid shore. Phaeopigment concentrations peaked in October ($50.78mg/m^2$) and at high shore ($61.58mg/m^2$) and were lowest in December ($22.53mg/m^2$) and at low shore ($15.28mg/m^2$). The number of microphytobenthos ranged from 78,556 to 287,898 cells/$cm^2$, reaching a maximum in April and a minimum in July. The diatoms Paralia sulcata, Navicula sp., and Delphines surirella were dominant at all tidal levels over the study period. Dinoflagellates were dominant in July at low shore, and blue-green algae were abundant between July and October at mid shore. In conclusion, species composition and primary production of microphytobenthos exhibited clear seasonal and vertical patterns.

• 한국해양공학회지
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• 제5권1호
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• pp.25-34
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• 1991

An accurate estimation of water level variation when thewaves propagate to the coastal regionis very important for the port and harbor development plan. This study describes the application of a hybrid element model to harbor oscillation problem due to the construction of shore structure and implementation of shore boundary. The site selected is Pusan Harbor area with the third development and the Artificial Island plan. The observed water level changes at the site are compared with the result of the numerical experiment. The model gives a very important prediction of water level changes for navigation and harbor design.

• 헤리티지:역사와 과학
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• 제51권3호
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• pp.72-87
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• 2018

본 연구는 월지의 서측 호안 일대에 존재했던 출수구(出水口)와 구거(溝渠)를 재조명하고, 서측 호안의 출수시설이 월지의 역사적 배수체계와 연관되었을 가능성에 주목하고 있다. 세부적으로는 출수구의 위치와 형태, 월지 북서측 구거와 서측 호안 출수구의 관계성, 서측 호안 출수시설의 조성시기와 성격을 중점적으로 고찰하였다. 1975년 발굴조사로 확인된 서측 호안의 출수구는 1922년 실측도면에 기록된 수낙구(水落口)와 동일시설로 판단된다. 따라서 1920년대 이전부터 월지의 서측 호안에는 별도의 출수시설이 존재했을 가능성이 높다. 서측 호안 출수구는 장방형 석재를 가공한 시설이며, 수위조절을 위한 4개의 배수공(排水孔)이 설치되어 있었다. 배수공을 통한 출수방식은 월지 북측 호안에서 조사된 출수시설과 동일하다. 1913년 제작된 지적도에서는 월지의 북서측 외곽으로 구거가 확인된다. 구거와 출수구는 근거리에 위치하며, 동일한 축선을 형성하고 있었다. 따라서 구거와 출수구는 월지의 배수체계와 연관된 유기적 시설로 판단된다. 특히 월지 북서측 구거는 서측 호안 출수시설의 조성시기를 1910년대 이전으로 소급할 수 있는 단초다. 출수구의 배수공을 통해 유입된 물은 구거를 통해 월지의 북서측 일대로 배출되었다. 서측 호안 출수시설의 조성시기와 성격은 두 가지 측면에서 해석된다. 첫 번째는 월지가 농업용 저수지로 기록되었다는 점, 월지의 북서측 일대가 농경지로 이용되었다는 점에 근거한 '조선시대의 농업용 관개시설'이다. 두 번째는 출수구가 월지의 수제선(水際線)을 형성하는 하층 호안석축에 설치되었다는 점, 최상단 배수공의 높이가 월지의 만수위(滿水位)와 유사하다는 점에 근거한 '월지 조영 당시의 수위조절용 출수시설'이다. 관련 근거와 정황을 고려하면 후자의 가능성이 더욱 높다고 판단된다.

• 한국치위생학회지
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• 제12권3호
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• pp.513-520
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• 2012

Objectives : In this study, contact angle and shore D hardness were measured, and a shark fin test was conducted after selecting five addition silicon(Blu-Mousse, BM; EXABITE II, EX; PERFECT, PF; Regisil$^{(R)}$ Rigid, RE; Silagum$^{(R)}$, SI) in order to figure out the properties of elastomeric interocclusal recording materials and reduce errors at interocclusal recording. 8) Methods : A contact angle was measured using a contact angle analyzer. After placing a drop of liquid on the surface of the specimens of interocclusal recording materials, a contact angle was photographed with a CCD camera on the equipment. In terms of a shark fin test, interocclusal recording materials were mixed for the time proposed by the manufacturer and inserted into the split ring of the Shark fin device. Twenty (20) seconds exactly, a metal rod was removed to make the materials slowly absorbed. Once they hardened, fin height was measured with a caliper after separating molds and trimming the specimens. The shore D hardness was measured with a shore D hardness tester(Model HPDSD, Hans Schmidt & Co. Gmbh, Germany) in sixty (60) minutes after fabricating specimens. In each experiment, five specimens, mean and standard deviation were calculated. A one-way ANOVA test was performed at the p>0.05 level of significance. In terms of correlation among the tests, Pearson correlation coefficient was estimated. For multiple comparison, Scheffe's test was carried out. Results : A contact angle was the highest in EX with $99.23^{\circ}$ (p<0.05) while the result of the shark fin test was the longest in RE with 5.45mm. SI was the lowest (0.27mm) with statistical significance. Among the interocclusal recording materials, significant difference was observed in terms of means (p<0.05). The shore D hardness was the highest in SI with 31.0 while RE was significantly low with 16.4 (p<0.05). Among the materials, statistically significant difference was observed in terms of means when compared to the rest materials (RE), BM, RE and SI (PF and EX) and the remaining materials (BM and SI) (p<0.05). In terms of correlations among the tests, a negative correlation occurred between shore D hardness and shark fin test(r=-0.823, p=0.000). Conclusions : According to the study above, it is necessary to understand the properties of interocclusal recording materials and consider contact angle, shark fin test and properties of shore D hardness to select appropriate materials.

• 한국해양공학회지
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• 제37권2호
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• pp.68-79
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• 2023

Even though submerged breakwater reduces incident wave energy, it redistributes the coastal area's wave-induced current, sediment transport, and morphological change. This study examines the coastal hydrodynamics and the morphological response of a wave-dominated beach with submerged breakwaters installed through field observation and quasi-3D numerical modeling. The pre-and post-storm bathymetry, water level, and offshore wave under storm forcing were collected in Bongpo Beach on the East coast of Korea and used to analyze the coastal hydrodynamic response. Four vertically equidistant layers were used in the numerical simulation, and the wave-induced current was examined using quasi-3D numerical modeling. The shore normal incident wave (east-northeast) generated strong cross-shore and longshore currents toward the hinterland of the submerged breakwater. However, the oblique incident wave (east-southeast) induced the southeastward longshore current and the sedimentation in the northeast area of the beach. The results suggested that the incident wave direction is a significant factor in determining the current and sediment transport patterns in the presence of the submerged breakwaters. Moreover, the quasi-3D numerical modeling is more appropriate for estimating the wave transformation, current, and sediment transport pattern in the coastal area with the submerged breakwater.

• 전력전자학회논문지
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• 제20권1호
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• pp.1-10
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• 2015

This paper proposes a control algorithm for permanent magnet synchronous generators with a back-to-back three-level neutral-point clamped voltage source converter in a medium-voltage off-shore wind power system under unbalanced grid conditions. Specifically, the proposed control algorithm compensates for unbalanced grid voltage at the PCC (Point of Common Coupling) in a collector bus of an off-shore wind power system. This control algorithm has been formulated based on symmetrical components in positive and negative synchronous rotating reference frames under generalized unbalanced operating conditions. Instantaneous active and reactive power is described in terms of symmetrical components of measured grid input voltages and currents. Negative sequential component of AC input current is injected into the PCC in the proposed control strategy. The amplitude of negative sequential component is calculated to minimize the negative sequential component of grid voltage under the limitation of current capability in a voltage source converter. The proposed control algorithm enables the provision of balanced voltage at the PCC resulting in the high quality generated power from off-shore wind power systems under unbalanced network conditions.

• 한국정보통신학회논문지
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• 제13권3호
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• pp.537-545
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• 2009

최근 육상에서 원격진료에 대한 많은 연구와 기술개발이 수행되어 왔으나 해상에는 적용되지 않고 있다. 본 논문에서는 해상의 선박에서 긴급한 응급의료 지원상황이 발생했을 때 환자의 생체정보를 측정하여 원격지에 있는 의사에 게 전달하고 진료 받기 위한 원격 진료 시스템을 설계하고 구현하였다. 현재 해상에서 응급상황이 발생 시 주로 무선통신이나 위성 전화를 통한 단순한 문답에 의한 의학 자문에 의존하고 있다. 본 논문에서는 이를 개선하기 위해 전문적으로 진단에 필요한 환자의 기초 신체상태 즉, 혈압, 맥박, 호흡, 심전도, 체온 및 영상 등을 선박 내 현장에서 측정한 후 전문 의료진에 원격 전송함으로써 보다 정확한 처방이 가능하고 보다 높은 의료서비스를 제공할 수 있도록 개발하였다. 개발된 시스템으로 해상상의 응급환자에게 의료 서비스의 질을 높여 응급상황에 적절히 대처할 수 있다고 본다.

• 전기학회논문지
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• 제63권9호
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• pp.1192-1198
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• 2014

With an increase in the penetration of offshore wind farm, the need of an accurate economic evaluation of offshore wind farm has become crucial. This paper presents an economic evaluation method of offshore wind farm in Korea reflecting the cost of offshore wind farm infrastructure (offshore substation, submarine cable and foundation) in its cost model. Each cost of offshore substation, submarine cable, and foundation is represented as a function of installed capacity, distance to shore, and water level, respectively. We have applied the method to the case study of offshore in Jeju Island and analyzed the economics under various conditions. The results show that the distance to shore is of importance in economics of offshore wind farm.