• Journal of the Korean Geographical Society
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• v.28 no.4
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• pp.321-355
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• 1993

This paper focuses on the geographical pattern of financial activities in the Korean urban system during 1975-1990, based on the assumption that financial activities can reveal control points in Korea's urban economy. In terms of spatial evolution of financial insitutions, different locational characteristics are revealed among different types of financial institutions, implying the role of urban hierarchy. Financial resources are highly concentrated in the capital region, Seoul and Kyonggi Province. Both centralization trends into the large metropolitan cities and relative declines of medium and small cities within the Korean urban system, have been experienced over the study period. Financial activities sustain relatively stable hierarchical structure in the urban hierarchy. Regarding the financial flows, dominant flow zones centered on major metropolitan cities are identified, clearly showing a prominant role of Seoul in financial flows in the entire urban system.

• The Korean Journal of Petroleum Geology
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• v.8 no.1_2 s.9
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• pp.1-43
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• 2000

A comparison study for understanding a stratigraphic response to tectonic evolution of sedimentary basins in the Yellow Sea and adjacent areas was carried out by using an integrated stratigraphic technology. As an interim result, we propose a stratigraphic framework that allows temporal and spatial correlation of the sedimentary successions in the basins. This stratigraphic framework will use as a new stratigraphic paradigm for hydrocarbon exploration in the Yellow Sea and adjacent areas. Integrated stratigraphic analysis in conjunction with sequence-keyed biostratigraphy allows us to define nine stratigraphic units in the basins: Cambro-Ordovician, Carboniferous-Triassic, early to middle Jurassic, late Jurassic-early Cretaceous, late Cretaceous, Paleocene-Eocene, Oligocene, early Miocene, and middle Miocene-Pliocene. They are tectono-stratigraphic units that provide time-sliced information on basin-forming tectonics, sedimentation, and basin-modifying tectonics of sedimentary basins in the Yellow Sea and adjacent area. In the Paleozoic, the South Yellow Sea basin was initiated as a marginal sag basin in the northern margin of the South China Block. Siliciclastic and carbonate sediments were deposited in the basin, showing cyclic fashions due to relative sea-level fluctuations. During the Devonian, however, the basin was once uplifted and deformed due to the Caledonian Orogeny, which resulted in an unconformity between the Cambro-Ordovician and the Carboniferous-Triassic units. The second orogenic event, Indosinian Orogeny, occurred in the late Permian-late Triassic, when the North China block began to collide with the South China block. Collision of the North and South China blocks produced the Qinling-Dabie-Sulu-Imjin foldbelts and led to the uplift and deformation of the Paleozoic strata. Subsequent rapid subsidence of the foreland parallel to the foldbelts formed the Bohai and the West Korean Bay basins where infilled with the early to middle Jurassic molasse sediments. Also Piggyback basins locally developed along the thrust. The later intensive Yanshanian (first) Orogeny modified these foreland and Piggyback basins in the late Jurassic. The South Yellow Sea basin, however, was likely to be a continental interior sag basin during the early to middle Jurassic. The early to middle Jurassic unit in the South Yellow Sea basin is characterized by fluvial to lacustrine sandstone and shale with a thick basal quartz conglomerate that contains well-sorted and well-rounded gravels. Meanwhile, the Tan-Lu fault system underwent a sinistrai strike-slip wrench movement in the late Triassic and continued into the Jurassic and Cretaceous until the early Tertiary. In the late Jurassic, development of second- or third-order wrench faults along the Tan-Lu fault system probably initiated a series of small-scale strike-slip extensional basins. Continued sinistral movement of the Tan-Lu fault until the late Eocene caused a megashear in the South Yellow Sea basin, forming a large-scale pull-apart basin. However, the Bohai basin was uplifted and severely modified during this period. h pronounced Yanshanian Orogeny (second and third) was marked by the unconformity between the early Cretaceous and late Eocene in the Bohai basin. In the late Eocene, the Indian Plate began to collide with the Eurasian Plate, forming a megasuture zone. This orogenic event, namely the Himalayan Orogeny, was probably responsible for the change of motion of the Tan-Lu fault system from left-lateral to right-lateral. The right-lateral strike-slip movement of the Tan-Lu fault caused the tectonic inversion of the South Yellow Sea basin and the pull-apart opening of the Bohai basin. Thus, the Oligocene was the main period of sedimentation in the Bohai basin as well as severe tectonic modification of the South Yellow Sea basin. After the Oligocene, the Yellow Sea and Bohai basins have maintained thermal subsidence up to the present with short periods of marine transgressions extending into the land part of the present basins.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.188-197
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• 2020

Termites play an important role as decomposers of the forest ecosystem, while simultaneously causing enormous damage to wooden structures. Currently, two species of subterranean termites have been reported in Korea, and termite damage to historical wooden buildings is occurring nationwide due to climate change, forest fertility, and the locational characteristics of historical wooden buildings. Subterranean termites make their nests underground or inside timber. Termites move underground and access wooden structures through the lower parts of the buildings, adjacent to the ground. Once termites attack the wooden structures, it not only spoils the authenticity of cultural heritage structure, but also hampers structural stability due to the decrease in the strength of the material. Therefore, it is important to prevent termite damage before it occurs. Chemical treatments are mainly used in Korea to control and prevent the damage. In foreign countries, physical barriers are also used to prevent entry to wooden buildings, along with chemical treatments. Physical barriers involve installing nets or particles that termites cannot pass through in the lower part of the building, around the pipes, and between the edges of the building or exterior walls and interior materials. Advantages of a physical barrier are that it is an eco-friendly method, maintains long-term effect after installation, and does not require the use of chemical treatments. Prior to applying physical barriers, studies into the characteristics of termite species must be undertaken. In this study, we evaluated the minimum passage size that each caste of Reticulitermes speratus kyushuensis can move through. We found that workers, soldiers, and secondary reproductive termites were able to pass through diameters of 0.7mm, 0.9mm, and 1.1mm respectively. Head height of termites was an important factor in determining the minimum passing size. Results from the current study will be used as a basis to design the mesh size for physical barriers to prevent damage by termites in historical wooden buildings in Korea.

• Journal of the Korean Orthopaedic Association
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• v.55 no.4
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• pp.281-293
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• 2020

An anterior cruciate ligament (ACL) reconstruction is one of the most frequent surgical procedures in the knee joint, but despite the better understanding of anatomy and biomechanics, surgical reconstruction procedures still fail to restore rotational stability in 7%-16% of patients. Hence, many studies have attempted to identify the factors for rotational laxity, including the anterolateral ligament (ALL), but still showed controversies. Descriptions of the ALL anatomy are also confused by overlapping nomenclature, but it is usually known as a distinctive fiber running in an anteroinferior and oblique direction from the lateral epicondyle of the femur to the proximal anterolateral tibia, between the fibular head and Gerdy's tubercle. The importance of the ALL as a secondary restraint in the knee has been emphasized for successful ACL reconstructions that can restore rotational stability, but there is still some controversy. Some studies reported that the ALL could be a restraint to the tibial rotation, but not to anterior tibial translation. On the other hand, some studies reported that the role of ALL in rotational stability would be limited as a secondary structure because it bears loads only beyond normal biomechanical motion. The diagnosis of an ALL injury can be performed by a physical examination, radiology examination, and magnetic resonance imaging, but it should be assessed using a multimodal approach. Recently, ALL was considered one of the anterolateral complex structures, as well as the Kaplan fiber in the iliotibial band. Many studies have introduced many indications and treatment options, but there is still some debate. The treatment methods are introduced mainly as ALL reconstructions or lateral extra-articular tenodesis, which can achieve additional benefit to the knee stability. Further studies will be needed on the indications and proper surgical methods of ALL treatment.

• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.388-404
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• 2024

The focus of conserving plant diversity at the national level includes endemic species restricted to specific regions. This study thus aimed to investigate and evaluate the current distribution status of the Pulsatilla tongkangensis Y.N. Lee & T.C. Lee, one of Korea's endemic plants. The study also examined the vegetation environment of its habitat and assessed the structure of each population. Furthermore, the performance variable of each population was comparatively evaluated, and its annual growth characteristics were also observed. The distribution area of the P. tongkangensis is largely divided into limestone cliffs, ridge rocks, mountain peaks in limestone regions, and sandy soil areas resulting from weathering. Plants in the same distribution area were categorized based on their geographical location, which reflected their respective habitats. According to the population structure evaluated using the number of measured leaves numbers, the plants were categorized into stable and relatively unstable populations. A relatively young population was observed at the top of mountains and rocky ridges of limestone areas and sandy soil areas resulting from weathering. The number of mature individuals was the highest in the population observed around limestone cliffs. In contrast, the population near the top of the limestone mountain range had more leaves , but the plants were of short stature and had the fewest inflorescences. The individuals distributed in limestone cliffs grew, produced, and dispersed seeds for an extended period following establishment. The growth of individuals was limited due to environmental factors in the habitat of distribution areas, including ridges, mountain tops in limestone regions, and sandy soil areas resulting from weathering. It was assessed to have a comparatively brief life cycle compared to that of the plants found on limestone cliffs. P. tongkangensis began flowering in early spring, and both fruit maturation and seed dispersal were completed before the onset of summer. The habitats were determined to receive around seven hours of sunlight per day during the summer, which was considered suitable for establishing a life cycle for the P. tongkangensis, a species requiring strong sunlight for growth to establish and success in a dry environment. Considering the status data gathered from this study, the P. tongkangensis was classified as an endangered species (EN). In addition, the collected data are expected to provide important information for the IUCN Red List of Threatened Species. Therefore, we proposed that the P. tongkangensis holds significant value as a core distribution site, given the observation of species with diverse characteristics on limestone cliffs in Pyeongchang-gun and Jeongseon-gun, Gangwon-do.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.181-190
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• 2004

A new inelastic design method performing iterative calculations using secant stiffness was developed. Since the proposed design method uses linear analysis, it is convenient and stable in numerical analysis. At the same time, the proposed design method can accurately estimate the inelastic strength and ductility demands of the members by performing iterative calculation. In the present study, the procedure of the proposed design method was established. Design examples using the proposed method were presented, and its advantages were highlighted by comparisons with existing design methods using elastic or plastic analysis. Unlike the existing inelastic design methods performing the preliminary design on the structure and checking its validity using nonlinear analysis, the proposed integrated analysis-design method can directly calculate the strength and ductility demands of each member. In addition, the proposed design method can address the inelastic design strategy intended by the engineer, such as strength and ductility limits of members and the design concept of strong-column and weak-beam. As a result, economical and safe design can be achieved.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.6
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• pp.267-271
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• 2004

Lithium cobalt oxide $(LiCoO_2)$ cathode powders for rechargeable battery have been successfully prepared using urea hydrolysis method. The obtained hydrolysis-derived precursors with different Li/Co molar ratio were calcined at various temperatures. Low temperature phase $(LT-LiCoO_2)$ and high temperature phase $(HT-LiCoO_2)$ were obtained after calcination at $500^{\circ}C$ for 2 hr, and phase transformation from $LT-LiCoO_2{\;}to{\;}HT-LiCoO_2$ was completely occurred over $700^{\circ}C$. The layered structure of $LiCoO_2$ was well developed with a rise in the calcination temperature. Charge-discharge test show that the lithium cobalt oxide with 1.2 molar ratio prepared at $800^{\circ}C$ has an initial discharge capacity as high as 152 mAh/g, and the relatively stable cycling characteristic with 9.2 % of capacity fading was obtained after 40th charge-discharge test.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.8
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• pp.50-58
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• 2009

Fourth generation mobile communication network have the technology of extensive form include basic service technology and it has been developed from the radio access technology and network topology. Not only fourth generation mobile communication network have basically done new highspeed radio access technology which is suitable to high and low speed environment of transfer, but also it is possible that they have been made for freely vertical handover. ETRI also has made fourth generation mobile communication network which is WiNGS(Wireless Initiative for Next Generation Service) satisfied that demand. This paper is made by lossless handover method through the local retransmission ARQ agent that is one of the main technology of fourth generation mobile communication network. Lossless handover method through local retransmission ARQ agent has been basically made by WiNGS and it was better than original local retransmission of layer by simulation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.6
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• pp.493-500
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• 2014

Nonlinear characteristics of cellular counterflow diffusion flame near the radiative extinction limit at large Damk$\ddot{o}$hler number are numerically investigated. Lewis number is assumed to be 0.5 and flame evolution is calculated by imposing an infinitesimal disturbance to a one-dimensional(1-D) steady state flame. The early stage of nonlinear development is very similar to that predicted in a linear stability analysis. The disturbance with the wavenumber of the fastest growing mode emerges and grows gradually. Eventual, an alternating pattern of reacting and quenching stripes is developed. The cellular flame temperature is higher than that of 1-D flame because of the gain of the total enthalpy. As the Damk$\ddot{o}$hler number is further increased, the shape of the cell becomes circular to increase the surface area per unit reacting volume. The cellular flames do not extinguish but survive even above the 1-D steady state extinction condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.164-172
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• 2014

Recently, as the number of IoT (Internet of Things) devices for personal or home intelligence increases, the need for unified control and cooperative utilization is required. This paper presents a novel idea, proposes methods for virtualizing Internet of Things (IoT) devices and hosting them on the home AP instead of relying on a cloud service or purchasing a new device to do so. For this, the process and profile of the IoT gadgets need to be virtualized into JavaScript-based objects. Then, to execute and control the instances of the virtualized IoT objects on the wireless AP, a novel instance management method and their interfaces are designed. The implementation and performance section demonstrates the proposed system's stability and operability by showing the stress test results while the wireless AP is running for its wireless routing.