• Journal of Korean Society for Geospatial Information Science
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• v.13 no.1 s.31
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• pp.55-61
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• 2005

Digital Elevation Model (DEM) generation from remotely sensed imagery is crucial for a variety of mapping applications such as ortho-photo generation, city modeling. High resolution imaging satellites such as SPOT-5, IKONOS, QUICK-BIRD, ORBVIEW constitute an excellent source for efficient and economic generation of DEM data. However, prerequisite knowledge in the areas of sensor modeling, epipolar resampling, and image matching is required to generate DEM from these high resolution satellite imagery. From the above requirements, epipolar resampling emerges as the most important factors. Research attempts in this area are still in high demand and short supply. Another cause that adds to the complication of the problem is that most studies of DEM generation from IKONOS scenes have been based on rational function model. In this paper, we proposed a new methodology for DEM generation from satellite scenes using parallel projection model which is sensor independent, makes it possible for sensor modeling and epipolar resampling by only few control points. The performance and feasibility of the developed methodology is evaluated through real dataset captured by IKONOS.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.101-108
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• 2011

Construction of the Jangbogo antarctic station was planned, and it requires detailed information on topography of the area around the station. The purpose of this research is to generate the topographic map to construct the Jangbogo antarctic station using the satellite image. To do this, surveying and pre-test of equipment were conducted. In addition, for sensor modeling of the GeoEye-1 satellite image, RPC-bias correction was done, and it showed that at least two control points are required. In generating the map, a 1/2,500 scale was deemed suitable in consideration of resolution of the image and the fact that supplementary topographic surveying would be impossible. In order to provide detailed information on the topography around the Jangbogo station, the digital elevation model based on image matching was created, and compared with GPS-RTK data, accuracy of vertical location about 0.6m was exhibited.

• Journal of Distribution Science
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• v.14 no.10
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• pp.81-91
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• 2016

Purpose - This study proposes a strategic model for the late mover to effectively penetrate an industry that is dominated by a leading company. Thus, this study presents strategic implications for several late movers in overcoming the advantages of the leading company. Research design, data, and methodology - This study begins with a literature review followed by the formation of a strategic model that consists of: Repositioning, Utilization of Competence, Strategic Leadership, and Innovation. Specifically, this research analyzes LG Electronics (LG) as an example and investigates how LG infiltrates and grows in the water purifier market, overcoming the advantages of the powerful leading company. Results - The major steps taken by LG are summarized into four. First, LG studied the market, which had been conventionally treated as a single market. To penetrate the market, LG founded a new, special market segment. Subsequently, LG further segmented the market, executing a marketing strategy for each segment. Second, the unbending will of top managers was a key factor that addressed the challenge persistently. Third, even though LG was the late mover in the water purifier market, it had several technology competences such as compressor, refrigeration cycles, and algorithms. LG had profound knowledge in technology and used it effectively. Fourth, LG created a premium market through three innovative and distinguished factors such as the stainless water tank, sterilization service, and luxury design. Conclusions - This research draws four key findings from the example of the late mover in the water purifier industry: the reestablishment of a strategic position based on environmental change is an effective strategy for the late mover; strategic leadership is an important motive to generate late mover performance; and the late mover can utilize its existing knowledge and resources to overcome the first mover, such as presenting new added value compared to existing products as an effective catch-up strategy. Consequentially, through the study of performance determinants and the market penetration strategy of the late mover, this research has significance in providing basic material for companies trying to penetrate the market.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.629-632
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• 2007

While conventional interferometric SAR (InSAR) technique is an excellent tool for displacement observation, it is only sensitive to one-dimensional deformation along the satellite's line-of-sight (LOS). Recently, a multiple aperture interferogram (MAI) technique has been developed to overcome this drawback. This method successfully extracted along-track displacements from InSAR data, based on split-beam InSAR processing, to create forward- and backward- looking interferograms, and was superior to along-track displacements derived by pixel-offset algorithm. This method is useful to measure along-track displacements. However, it does not only decrease the coherence of MAI because three co-registration and resampling procedures are required for producing MAI, but also is confined to a suitable interferometric pair of SAR images having zero Doppler centroid. In this paper, we propose an efficient and robust method to generate MAI from interferometric pair having non-zero Doppler centroid. The proposed method efficiently improves the coherence of MAI, because the co-registration of forward- and backward- single look complex (SLC) images is carried out by time shift property of Fourier transform without resampling procedure. It also successfully removes azimuth flat earth and topographic phases caused by the effect of non-zero Doppler centroid. We tested the proposed method using ERS images of the Mw 7.1 1999 California, Hector Mine Earthquake. The result shows that the proposed method improved the coherence of MAI and generalized MAI processing algorithm.

• Journal of the korean society of oceanography
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• v.37 no.3
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• pp.169-177
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• 2002

An eddy-resolving free-surface primitive-equation model with nonlinear terrain-following coordinates is established to study the exchange of water masses among the Asian marginal seas and their adjacent waters. A curvilinear coordinate system is used to generate the horizontal grid with a variable resolution for the regional oceans from $5^{\circ}$S to $45^{\circ}$N and $100^{\circ}$E to $155^{\circ}$E. The higher resolution region has about a 10 km by 10 km grid covering the complex geometry of the coastal marginal seas, while the lower resolution region has about a 30 km by 30 km grid covering the eastern Pacific. The model is initialized by the Levitus annual climitology and forced by the monthly mean air-sea fluxes of momentum, heat, and freshwater derived from the Comprehensive Ocean-Atmosphere Data Set. High-resolution and low-viscosity are identified as the key factors for a better representation of the exchange of waters through narrow straits and passages between the marginal seas and their adjacent waters. The dynamics of the loop currents and eddies in the South China Sea and Celebes Sea are examined in detail. It has found that the anticyclonic loop and detached eddies from the Kuroshio through the Luzon Strait play an important role in transporting warm and salty water into the South China Sea, while the cyclonic circulation of the Mindanao Current in the Celebes Sea plays a role in contributing cold water to the Indonesian throughflow. The deep undercurrent of the western Pacific is shown to provide fresher water to the South China Sea and Celebes Sea. These modeling results suggest that the exchange processes via the narrow straits and passages are of fundamental importance to the maintenance of water masses for the marginal sea region.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.46-59
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• 1998

This paper presents shape design, surface construction, and cutting path generation for the surface of marine ship propeller blades. A propeller blade should be designed to satisfy performance constraints that include operational speed which impacts rotations per minutes, stresses related to deliverable horst power, and the major length of the marine ship which impacts the blade size and shape characteristics. Primary decision variables that affect efficiency in the design of a marine ship propeller blade are the blade diameter and the expanded area ratio. The blade design resulting from these performance constraints typically consists of sculptured surfaces requiring four or five axis contoured machining. In this approach a standard blade geometry description consisting of blade sections with offset nominal points recorded in an offset table is used. From this table the composite Bezier surface geometry of the blade is created. The control vertices of the Hazier surface patches are determined using a chord length fitting procedure from tile offset table data. Cutter contact points and path intervals are calculated to minimize travel distance and production time while maintaining a cusp height within tolerance limits. Long path intervals typically generate short tool paths at the expense of increased however cusp height. Likewise, a minimal tool path results in a shorter production time. Cutting errors including gouging and under-cut, which are common errors in machining sculptured surfaces, are also identified for both convex and concave surfaces. Propeller blade geometry is conducive to gouging. The result is a minimal error free cutting path for machining propeller blades for marine ships.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.513-520
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• 2014

An unmanned aerial vehicle (UAV) should be designed to be as small and lightweight as possible to optimize the efficiency of changing the blade shape to enhance the aerodynamic performance, such as the thrust and power. In this study, a computational fluid dynamics (CFD) simulation of an unmanned multi-rotor aerial vehicle in hover mode was performed to explore the thrust performance in terms of the blade rotational speed and blade shape parameters (i.e., taper ratio and twist angle). The commercial ADINA-CFD program was used to generate the CFD data, and the results were compared with those obtained from blade element theory (BET). The results showed that changes in the blade shape clearly affect the aerodynamic thrust of a UAV rotor blade.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3066-3079
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• 2016

Recent years have witnessed a dramatic increase in topology research of wireless sensor networks (WSNs) where both energy consumption and survivability need careful consideration. To balance energy consumption and ensure survivability against both random failures and deliberate attacks, we resort to complex network theory and propose an energy-aware preferential attachment (EPA) model to generate a robust topology for WSNs. In the proposed model, by taking the transmission range and energy consumption of the sensor nodes into account, we combine the characters of Erdős -Rényi (ER) model and Barabasi-Albert (BA) model in this new model and introduce tunable coefficients for balancing connectivity, energy consumption, and survivability. The correctness of our theoretic analysis is verified by simulation results. We find that the topology of WSNs built by EPA model is asymptotically power-law and can have different characters in connectivity, energy consumption, and survivability by using different coefficients. This model can significantly improve energy efficiency as well as enhance network survivability by changing coefficients according to the requirement of the real environment where WSNs deployed and therefore lead to a crucial improvement of network performance.

• Journal of Fashion Business
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• v.17 no.6
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• pp.28-43
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• 2013

Recent trends toward the collaborations among various sectors of academia and research areas have brought interests and significances in new activities especially in the fashion and textile areas. One of the collaboration examples is the recent research projects on 3D virtual clothing systems based on the 3D CAD software. The 3D virtual clothing systems provide simulated apparels with high degrees of fidelity in terms of color, texture, and structural details. However, since real fabrics exhibit strong nonlinearity, anisotropy, viscoelasticity, and hysteresis, the 3D virtual clothing systems need fine tuning parameters for the simulation process. In this study, characteristics of silk fabrics, which are woven by using degummed silk and raw silk yarns, are being analyzed and compared. Anisotropic properties may be measured as warp and filling direction properties separately in woven fabrics, such as warp tensile stress or filling bending rigidity. Hysteretic properties may be measured as bending hysteresis or shear hysteresis by using KES measurements. These data provide deformation-force relationships of the fabric specimen. Three-dimensional effects obtained when using these characteristic fabrics are also analyzed. The methods to control the three-dimensional appearance of the sewn fabric specimens when utilizing a programmable microprocessor-based motor device, as prepared in this study, are presented. Based on the physical and mechanical properties measured when using the KES equipment, the property parameters are being into a 3-dimensional virtual digital clothing system, in order to generate a virtual clothing product based on the measured silk fabric properties.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.51-57
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• 2000

With the emergence of laser mapping systems, higher resolution DTM of urban area can be acquired and can be used to generate precise orthoimage. But, when the conventional orthoimage generation methods are applied to the area containing features with height difference such as cliffs, bridges, banks. elevated highways and buildings, they cause problems such as occlusion and double mapping. Therefore, this study proposes a new algorithm by modifying and refining conventional orthoimage generation methods. With this algorithm, areas which have occlusion are detected from the base image using camera orientation parameters and DTM. Also, detected areas are restored using alternative images which does not have occlusion in that area. This study can be distinguished from the other studies in the aspects that the proposed algorithm in this paper doesn't need information on building and that uses DTM data and orientation parameters.