• Title/Summary/Keyword: 경계 특성

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Comparative Analysis of Bathymetry in the Dongdo and the Seodo, Dokdo using Multibeam Echosounder System (다중빔 음향 측심기를 이용한 독도 동도와 서도 남부 연안 해저지형 비교 분석)

  • Lee, Myoung Hoon;Kim, Chang Hwan;Park, Chan Hong;Rho, Hyun Soo;Kim, Dae Choul
    • Economic and Environmental Geology
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    • v.50 no.6
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    • pp.477-486
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    • 2017
  • In this study, we analyze precise seabed geomorphology and conditions for comparing the nearshore areas of the Dongdo(East Island) and the Seodo(West Island) using detailed bathymetry data and seafloor backscattering images, in Dokdo, the East Sea. We have been obtained the detailed bathymetry data and the seafloor backscattering data. The survey range is about $250m{\times}250m$ including land of islets to the nearshore areas of the southern part of the Dongdo and the Seodo. As a result of bathymetry survey, the southern area of the Dongdo(~50 m) is deeper than the Seodo(~30 m) in the water depth. The survey areas are consist of extended bedrocks from land of the Dongdo and the Seodo. The underwater rock region of the Seodo is larger than the Dongdo. In spite of similar extended rocks features from islets, there are some distinctive seabed characteristics between the southern nearshore areas of the Dongdo and the Seodo. The Talus-shaped seafloor environment formed by gravel and underwater rocks originating from the land of the Dongdo is up to about 15 m depth. And the boundary line of between extended bedrocks and seabottom is unclear in the southern nearshore of the Dongdo. On the other hand, the southern coast of the Seodo is characterized by relatively large scale underwater rocks and evenly distributed sediments, which clearly distinguish the boundary of between extended bedrocks and seafloor. This is because the tuff layers exposed to the coastal cliffs of the Dongdo are weak against weathering and erosion. It is considered that there are more influences of the clastic sediments carried from the land of the Dongdo compared with the Seodo. Particularly, the land of the Dongdo has been undergoing construction activities. And also a highly unstable ground such as faults, joints and cracks appears in the Dongdo. In previous study, there are dissimilar features of the massive tuff breccia formations of the Dongdo and the Seodo. These conditions are thought to have influenced the different seabed characteristics in the southern nearshore areas of the Dongdo and the Seodo.

Developing a New Area Study Methodology Suitable to the Globalization Era : With Revision of the Regional Geography of World-Systems. (세계화시대에 적실한 지역연구방법론 모색 -세계체제론적 지역지리학의 보완을 중심으로-)

  • Lee, Jae-Ha
    • Journal of the Korean association of regional geographers
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    • v.3 no.1
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    • pp.115-134
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    • 1997
  • We now live in the new era of globalization which implies the functional integration or increase of inter-dependency between internationally dispersed economic activities. As globalization impacts our various activities and daily lives, social sciences, including, geography, attempt to approach social phenomena from a global perspective. From this point of view. new regional geography, which has been articulated in recent social theory since the 1980s, also must adjust to these new world realities. This paper aims to search for a suitable methodology or approach to area study or regional geography in the era of globalization and to suggest the field of area study that Korean geographers should be concerned with in the future. This paper has reviewed the existing various methodologies of regional geography such as the ecological approach, the landscape approach. the areal differentiation approach, the system approach, the structuration theory, the spatial division of labour, and the world-system, which have deviced in the traditional and new regional geography. Peter Taylor's regional geography of world systems among them has an appropriate rationale of area study in the globalization era, because world-systems theory explains well globalization. However the regional geography of world-systems must be revised to become more suitable to the area-study approach in the globalization era. Firstly, the regional geography of world-systems explains that regions(historical regions) are made by general mechanisms of the capitalist world-economy that operate through social, economic, and political agents within regions such as individuals, households, social classes, economic enterprises, states, political movements, and many other organizations. But these mechanisms can also act through other regional agents of geographical location, natural conditions, and cultural characteristics. Therefore, the generating process of regions needs to be explained by locational, natural, and cultural elements in addition to social, economic, and political elements within regions. Secondly, Taylor's world-systems approach does not express composite characteristics of regions, because it focuses on the economic characteristics or position of regions within the world-economy. Regions incorporated into world-economy systems are not only changed economically, but also changed spatially, socially, culturally, and politically. Hence the world-systems approach must try to analyze these composite characteristics and their change of regions. Thirdly, The world-system approach proposed that the geography of regions within world-systems could be divided and analyzed as three regional types at the geographical scale such as international regions, state regions, and intra-state regions. However such a regionalization is usually not identified distinctly, because the geographical range of regions in world-systems shaped by economic boundaries of the general mechanisms of the world-economy is fluid and also occasionally overlaps with other political regions. Hence I propose that the world-systems approach should choose political boundaries of states and local autonomies in addition to economic boundaries for objective regionalization and systematic areal study. The revised regional geography of world-systems that I have suggested in this paper can be more effectively and properly applied to regional geography or area study in the globalization era. Globalization intensifies competition between states and also between local autonomies in the world. Therefore we must make efforts to study such areas or regions through the revised regional geography of world-system.

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Growth of Fe3O4 Particles and Their Magnetic Properties (Fe3O4 분말제조와 자기적 특성)

  • Kwon, Woo-Hyun;Lee, Seung-Wha;Chae, Kwang-Pyo;Lee, Jae-Gwang;Sur, Jung-Chul
    • Journal of the Korean Magnetics Society
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    • v.19 no.5
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    • pp.180-185
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    • 2009
  • Fe$_3$O$_4$ particles, prepared by a sol-gel method, were examined for their structural characteristic, particle shapes and sizes, and their magnetic properties. Two different chemical compositions (using a mol rate Fe$^{2+}$/Fe$^{3+}$ = 1/2 and only Fe$^{2+}$) and 2-methoxyethanol were used for making proper solutions. And the solutions were refluxed and dry in a dry oven and the samples were fired at 200$\sim$600$^{\circ}C$ in the N$_2$ atmosphere. The formation of single-phased spinel ferrite powders was identified with the X-ray diffraction measurement as they were fired at above 250$^{\circ}C$. The result of scanning electron microscopy measurement showed the increase of annealing temperature yielded the particle size increased. The magnetic transition was observed using the Mossbaur spectroscopy measurement. As the ferrite, prepared with the chemical composition (Fe$^{2+}$/Fe$^{3+}$ = 1/2), was fired at 250$^{\circ}C$, 78% of the ferrite had a ferrimagnetic property and 22% of the ferrite was non-magnetic. In case of preparing the sample with only Fe$^{2+}$ and annealed at 200$^{\circ}C$, it had a single phased spinel structure but its particle size was too small to be ferrimagnetic. The annealing temperature above 250$^{\circ}C$ made powders a spinel structure regardless of the preparation method. They had a typical soft magnetic property and their saturation magnetization and coercivity became larger as the annealing temperature increased.

Micromorphological Characteristics of Soil with Different Patent Materials (모재별 토양의 미세형태 특성)

  • Zhang, Yong-Seon;Jung, Seog-Jae;Kim, Sun-Kwan;Park, Chang-Jin;Jung, Yeon-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • v.37 no.5
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    • pp.293-303
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    • 2004
  • This experiment was conducted to investigate the direction or orientation of clay particle movement in argillic horizons (Bt) for clarifying the soil classification of soils. Soil samples were collected from 22 soil series containing Bt horizons. Physical and chemical characteristics and mineral and chemical compositions of clay in the soils were analyzed. Micoromorphological characteristics of the Bt horizons were also investigated with thin sections of the natural undisturbed and oriented soil samples. Average clay content in the Bt horizons was 28% and 1.33 times higher comparing to that in the surface layer. Soil pH was higher, but cation exchange capacity (CEC) and organic matter content were lower in Bt horizon than those in the surface layer. There was an evidence of clay accumulation in Bt horizons of all soil series examined except Bangog series. Although there was an increase of clay content in the horizons in Bangog series, the clay was not originated from illuviation process. The translocation of clay was in the order of an 2:1 expandable clay minerals > 2:1 non-expandable clay minerals > 1:1 clay minerals. The illuvial substances in argillic horizon were composed with clay, amorphous iron and opaque mineral. The micoromorphological features of Bt horizon were void coating, channel infilling and grain coating. There was an apparent boundary between clay coating and the groundmass in residuum and colluvium, but Bt horizon of alluvium was composed of a skew plane amputated by the physical operation.

The Analysis of the Ecological Characteristics of the Major Wetland Types in Seoul (서울시 주요 습지유형별 생태적 특성 분석)

  • 이경재;권전오;이수동
    • Korean Journal of Environment and Ecology
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    • v.17 no.1
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    • pp.44-55
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    • 2003
  • The wetland in the city could be mainly divided into the deep water type and the abandoned paddy type, so this study was conducted to analyze characteristics between the two types of the wetland. The former sample site was located near the Olympic village in Songpa-gu of Seoul, and the latter sample site was in front of the Mt. Bukhan fortress in Eunpyeong-gu of Seoul. The actual vegetation, vascular plants, and avian fauna were researched. In the actual vegetation, the deep water type had the broad surface of water and the emerged plant as Phragmites communis have grown widely, but the abandoned paddy type had the narrow sur-face of water and hydrophyte as Persicaria thunbergii have grown widely. It might be judged because the water depth of the abandoned paddy type were shallow wholly. And the floating-leaved plants and the free-floating planktonic plants were not observed such as Nymphaea tetragona var. angusta, Lemna paucicostata in the abandoned paddy type wetland. The wild birds were mainly observed at the edge of the wetland(at the edge of woodland) in the abandoned paddy type, but were observed equally in the deep water type. 28 families 433 species were observed at the former site and 32 families 365 species were observed at latter site. It was judged that the various topographical structure(habitat diversity) might make all items various.

Response Characteristics of the PZT Transducers during Glass Capillary Breakage (유리모세관 파괴시 방출된 탄성파에 대한 PZT 변환기의 응답특성)

  • Lee, Jong-Kyu
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.1
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    • pp.33-41
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    • 1998
  • The response characteristics of the PZT transducers during glass capillary breakage were studied at the epicenter of the glass plate. The PZT transducers had been made by using EC-65 PZT ceramics(supplied by Edo co.) with a constant area and a various thickness. The theoretical displacement and velocity at the epicenter of glass plate with an air boundary condition were calculated by assuming the point load of 1N force strength and a rise time of 280 ns with a ramped functional dependence, and the 1st pulses of the PZT transducer may be considered as the vertical velocity incident on the electrode of the PZT ceramic. The responses of the PZT transducer may be depended on the thickness mode of the PZT ceramic below 0.33 in the ratio of the thickness to the diameter of PZT ceramic, but the reponse of the PZT transducer may be depended on the other modes of PZT transducer in the addition of the thickness mode of the PZT ceramic above 0.33. The full time of half maximum at the 1st pulse was nearly 280 ns without a variation of applied breakage load and the resonant frequency of the PZT transducer, and then may be considered as the rise time of a AE source. The maximum amplitude of the 1st pulse depended on the incident vertical velocity and capacitance of the PZT transducer. Therefore, the full time of half maximum and maximum amplitude of the 1st pulse may be considered as the rise time and strength of acoustic emission source respectively.

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Characteristics of Water Temperature and Salinity in the Bottol Bada, Yeosu during Summer in 2010 (2010년 하계 보돌바다의 수온과 염분 특성)

  • Cho, Eun-Seob
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.4
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    • pp.301-306
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    • 2011
  • This study was determined to analysis the characteristics of water mass in the Bottol Bada, Yeosu in August, 2010 based on the data from the distribution of water temperature and salinity. Sampling was carried out a total of three times (i.e. July 29, August 13, and August 30, 2010) and performed at three stations. Observation was done during the period of time 10:00-15:00, indicating the decreasing tidal height and turn of tide. In July 29, thermocline was found at 4 m in St. 1, but the stratification did not observe in August 13 and August 30. The remarkable water temperature between surface and bottom was found in St. 2 and St. 3, whereas St. 1 did not find. A particular finding during this study showed a cold water mass at bottom layer from St. 2 and St. 3, which was first occurred in July 29 and persisted in August 30 without any of destruction. Water temperature had a remarkable fluctuation between surface and bottom, whereas salinity had a unique in St. 1. St. 2 and St. 3 showed the increasing salinity according to water depth in August 13 and August 30. Transparency had considerable fluctuations in St. 1 and St. 3 depending to sampling date, but St. 2 did not fluctuate. Consequently, the Bottol Bada had a significantly different water mass between inner and outer waters. Furthermore, strong irradiance and weak wind play an important role in developing the stratification between surface and bottom, in particular the introduction of offshore waters contribute to highly developing the stratification in the Bottol Bada during the period of August in 2010.

A Study on the Evaluation Method of Shielding Effectiveness using NFS in Near-Field Tests (근거리장에서 NFS를 사용한 차폐효율 평가방법에 관한 연구)

  • Park, Jungyeol;Song, Inchae;Kim, Boo-Gyoun;Kim, Eun-Ha
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.8
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    • pp.76-82
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    • 2016
  • In this paper, we evaluated shielding effectiveness (SE) of carbon nanotube (CNT) film using near field scanning (NFS) in near field analysis. We adopted CNT film with deposit carbon density of 5% and thickness of 1mm for evaluation of shielding characteristic. Using a test coupon analogized to an actual IC package, we measured SE according to measuring position and SE according to distances between the CNT film and the test coupon. As a result, the measured SE in the near field varied with frequency. Especially, the measured electric field SE in the center of the test coupon is better than that of the measured edge point of the test coupon where it is affected by fringing effect. The results show that the measured SE in the near field is affected not only by frequency but also by measurement environment such as position and height of the probe and height of shielding film. In conclusion, we should choose proper methods for SE measurement considering interference distance in the electronic control system because there is little correlation between the proposed evaluation method in the near field and ASTM D 4935-10.

Application of Fractal Dimension on Consistent Calculation of Coastline Length - Focused on Jeju Island (일관된 해안선 길이 산출을 위한 프랙탈 차원 적용 방안 연구 - 제주도를 중심으로 -)

  • Woo, Hee Sook;Kwon, Kwang Seok;Kim, Byung Guk;Cho, Seck Hyun
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.4
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    • pp.83-88
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    • 2016
  • The use of consistent coastlines is an important element for the systematic management of maritime boundaries and the interests of local governments. The Hydrographic and Oceanographic Agency conducted a preliminary survey for consistent coastline production, since 2001. As a result, the length of coastline was different by year. Because of the lack of systematic management, the use of incorrect data, etc. We also changed the coastline on the sea chart to show on a digital map for realization of terrain expression method. However, there was a variation in shoreline length due to various surveying techniques and shoreline extraction methods. In this paper, the characteristics of Jeju-do coastline were analysed by using a modified divider method of fractal dimension. The accuracy of the vectorization was determined by converting the actual distance in the Public Survey Amendment for proper divider use. With 1:5,000 and 1:25,000 digital maps of Jeju-si and Seogwipo-si each fractal dimensions were calculated. Jeju-si=1.14 and Seogwipo-si=1.12 in 1: 5,000. Jeju-si=1.13 and Seogwipo-si=1.10 in 1: 25,000. Calculated fractal dimension were correlated to data from digital maps. It was considered that complexity and scale of coastlines affected. In the future coastline length statistics and minimum ratio of calculated coastline length to original length need to be determined for consistency of coastline length statistics.

The Reality of Community through Social Network Analysis: the Case of 7 Sansa, Buddhist Mountain Monasteries in Korea (사회연결망 분석을 통해 본 지역공동체의 실제: 7개 산사, 한국의 산지승원을 중심으로)

  • Kim, Sook-Jin
    • Journal of the Economic Geographical Society of Korea
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    • v.20 no.1
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    • pp.49-69
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    • 2017
  • The crisis of western welfare states and the spread of neoliberalism opened up the debate on community question and paid attention to community to cope with diverse social crises. There has been increasing recognition for the need to see World Heritage in terms of place and local community which had formed it rather than an object for conservation separated from the place where it is located. In addition, the conservation and use of cultural heritage can lead to the region's sustainable development and in turn is possible with the region's overall development. However, the Operational Guidelines for the Implementation of the World Heritage Convention does not specify the definition and geographic extent of community. This paper considers place-based communities, Sahachons and religious communities, Sindohoes of seven Buddhist monasteries in preparation for inscription on the UNESCO World Heritage List, and analyzes social networks of these two types of communities to see their consistency with their general characteristics. Social networks analyses indicates that some monasteries show significant differences between Sahachons and Sindohoes, but others do not. This result implies that communities should be seen as processes of constantly reconstituting their features and boundaries under their specific surroundings which are also in constant changes, thus requiring empirical studies.