• 한국가시화정보학회:학술대회논문집
• /
• 2003.11a
• /
• pp.39-42
• /
• 2003

Leading edge extension(LEX) in a highly swept shape applied to a delta wing features the modern air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present 3-D stereo PIV includes the Identification of 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterion and so on. A delta wing model with or without LEX was immersed in a circulating water channel. Two high-resolution, high-speed digital cameras$(1280pixel\times1024pixel)$ were used to allow the time-resolved animation work. The present dynamic stereo PIV represents the complicated vortex behavior, especially, in terms of time-dependent characteristics of the vortices at given measuring sections. Quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing to make the easy understanding of the LEX effect or vortex emerging and collapse which are important phenomena occurring in the field of delta wing aerodynamics.

• Journal of Information Technology Application
• /
• v.3 no.1
• /
• pp.1-21
• /
• 2001

The explosive growth of the Internet and the increasing popularity of the World Wide Web have generated significant interest in the development of electronic commerce in a global online marketplace. The rapid adoption of the Internet as a commercial medium is rapidly expanding the necessity of Web advertisement as a new communication channel. if proper Web advertisement could be suggested to the right user, then effectiveness of Web advertisement will be raised and it will help company to earn more profit. So, this article describes a personalized advertisement technique as a part of intelligent customer services for an electronic newspaper provide. Based on customers history of navigation on the electronic newspapers pages, which are divided into several sections such as politics, economics, sports, culture, and so on, appropriate advertisements (especially, banner ads) are chosen and displayed with the aid of machine learning techniques, when customers visit to the site. To verify feasibility of the technique, an application will be made to one of the most popular e-newspaper publishing company in Korea.

• Journal of the Korean Geographical Society
• /
• v.40 no.4 s.109
• /
• pp.402-415
• /
• 2005

This study inquired the features of restructuring of shipbuilding industry and structure of community cooperation. The Sinhyeon-eup region has experienced rapid changes as a large shipyard location. Prior to Korea, Japan has developed the cooperation of company-community-residents relationships and the reorganization of location systems through division and accumulation system. The restructuring of shipbuilding industry in Korea have focused on the improvement of business environment. So they have not been efficiently settled in the accumulation and the cooperation structure between company and region. Japan established the organic cooperation structure of company and community before the large restructuring, while the shipbuilding industry city of our country commenced it with the crisis of community by the restructuring. In the Sinhyeon-eup region, The connecting ring among the production sections of a core company in center is established. However the structure of community cooperation is weak. The structure of community cooperation as local governance consist of company, pubic institution, local residents, and regional expert. This structure can be a rational channel in which it can not only strengthen the cohesion of the community, but also solve the present questions of the industrial city.

• Journal of Korea Water Resources Association
• /
• v.37 no.1
• /
• pp.55-66
• /
• 2004

The Hapchon Dam, located upstream of the Hwang River, Korea, was constructed in December, 1988. Due to the lack of storage of water, the dam gate has not been operated during last ten years. Thus, a new ecosystem has been established at the downstream part of the dam. This is not a common phenomenon which can be found elsewhere in the country. The present study investigates the effect of flow regime change on the river morphology and vegetation cover in the downstream river reach after the dam construction. The analysis of flow regime is carried out, and the changes in bed elevation and in channel cross sections are examined. Site investigations including tree ring tests are also performed. The increase in the vegetation cover is estimated by comparing aerial photographs taken before and after dam construction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.11a
• /
• pp.87-88
• /
• 2019

Leading Lights and Sector Lights provide a navigable channel, heading reference and a visual indication. Mariners can take easily a reference bearing or line of position. The Busan North Port needed to install a sector light to resolve blind sections because of Busan Port Redevelopment Project D-1 Block Construction Plan. And also the busan new port needed to install a sector light to give safety indication because navigation conditions will be changed due to removal of the to-island. For this reason, design development was made for installation of sector lights. In addition, the results of design development were compared with the AtoN simulation and verified. This paper is expected to be very useful for installing Sector Lights to guide the vessel to port safely in Korea.

• Journal of Korea Water Resources Association
• /
• v.43 no.2
• /
• pp.233-243
• /
• 2010

A method is proposed of estimating Muskingum-Cunge parameters for natural streams using cross-sectional and longitudinal channel geometry and roughness coefficient data. Firstly, for various water-surface levels at a cross section cross-sectional areas and hydraulic radii are calculated. Corresponding discharges are then calculated using Manning's equation. This procedure is repeated for all cross-sections in the reach. Finally, routing parameters are estimated from the calculated cross-sectional area and discharge value pairs by regression analysis. The procedures for estimating Muskingum-Cunge parameters are applied to the South Han River. Flows calculated by Muskingum-Cunge model with estimated parameters showed much better agreement with those by dynamic wave model in peak discharge, time to peak discharge, and normalized RMS errors than those calculated by the HEC-1 Muskingum-Cunge model.

• Publications of The Korean Astronomical Society
• /
• v.28 no.1
• /
• pp.7-13
• /
• 2013

We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the 'background' task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using 'background' task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1672-1677
• /
• 2004

Leading edge extension(LEX) in a highly swept shape applied to a delta wing features the modem air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present 3-D stereo PIV includes the Identification of 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterion and so on. A delta wing model with or without LEX was immersed in a circulating water channel. Two high-resolution, high-speed digital cameras($1280pixel{\times}1024pixel$) were used to allow the time-resolved animation work. The present dynamic stereo PIV represents the complicated vortex behavior, especially, in terms of time-dependent characteristics of the vortices at given measuring sections. Quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing to make the easy understanding of the LEX effect or vortex emerging and collapse which are important phenomena occurring in the field of delta wing aerodynamics.

• Journal of Advanced Navigation Technology
• /
• v.10 no.3
• /
• pp.205-212
• /
• 2006

In this paper, the numerical methods of searching the optimal position of optical phase conjugator (OPC) and the optimal dispersion coefficients of fiber sections are proposed, which are able to effectively compensate overall channels in $8{\times}40$ Gbps WDM system with non zero - dispersion shifted fiber (NZ-DSF) as an optical fiber. And the compensation characteristics in the system with two induced optimal parameters are compared with those in the system with the currently used mid-span spectral inversion (MSSI) in order to verify the availability of the proposed methods. It is confirmed that the compensation extents of the distorted 8-channel signals are improved within 2 dB power penalty by applying the induced optimal parameters into WDM system. It is also confirmed that two optimal parameters less related with the searching procedure of these optimal values, only if these depend on each other.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.12 no.3
• /
• pp.128-142
• /
• 2009

A lot of efforts have been made to resolve balancing problems between flux and source term and most finite volume models under development have been applied to simple channels such as imaginary and experimental channels. However, a number of numerical problems which can not be found in simple channels occur in the application to natural rivers and the problems should be resolved to apply finite volume models to natural rivers. In this study, 2D finite volume model which is applicable to natural rivers was developed and the accuracy of the developed model was validated through the application of partial dam break In addition, a simple and efficient 2D mesh generation method was suggested and the method can be accurately reflected to 2D mesh converted from surveyed cross sections in Han-river using GIS. The accuracy and applicability of the developed model on natural rivers were verified by performing simulation on Han-river using the generated mesh and comparing computed water elevation with measured water elevation.