• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.27-31
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• 2017

A high-performance wideband transition from double-sided parallel-stripline (DSPSL) to coplanar stripline (CPS) is proposed. This transition is designed by consideration of gradual field transformation and optimal impedance matching between DSPSL and CPS. Clear design guidelines of proposed transition are provided to determine the ground shape and the transition length. The fabricated transition exhibits less than 0.7 dB insertion loss per transition for frequencies from 6.2 to 18.2 GHz, and less than 1.25 dB insertion loss to over 30 GHz.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.211-220
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• 2003

As Geographic Information Systems represent three dimensional topological information, The Systems provide accurate and delicate services for users. In order to execute three dimensional topological operations, a dimensional transformation and heterogeneous spatial models should be used. However, the existing systems that use the dimensional transformation and the heterogeneous models, is not only difficult to operate the spatial operators, but also happened to support non-interoperability. Therefore, in order to solve the problems, we proposed three dimensional spatial object models that supported two dimensional object models and implemented them to show validity of the proposed models. When designing the three dimensional topological operators, we used 3DE-9IM which extended DE-9IM to support three dimensional concepts, and implemented operators on the component environment with object oriented concepts. The proposed three dimensional spatial object models and topological operators can support interoperability between systems, and execute spatial queries efficiently on three dimensional spatial objects.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.65-74
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• 2012

In this paper, we explore the application of 2-D dual-tree discrete wavelet transform (DDWT), which is a directional and redundant transform, for image coding. DDWT introduces limited redundancy and allows the transform to provide approximate shift invariance and directionally selective filters while preserving the usual properties of perfect reconstruction and computational efficiency with good well-balanced frequency responses. Also, quincunx lattice yields a non separable 2D-wavelet transform, which is also symmetric in both horizontal and vertical direction. And non-separable wavelet transformation can generate sub-images of multiple degrees rotated versions. The proposed 2-D non-separable DDWT can provide efficient approximation for directional features of images schemes, such as edges and contours in images that are not aligned with the horizontal or vertical direction. Finally, non-separable image processing using DDWT services good performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.91-96
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• 2008

In this paper, a monopulse fled for three mode $2{\times}2$ array feed horn antenna was designed. Gain of single feed was 8.25dB. Increasing property of gain and rectangular waveguide and reflection of free space is decreased because it has structure extending to electric plane at connected part from transformation to free space. When fled port1 and port2 is placed vertically and thickness of aperture hem is reduced, isolation is satisfied with property of lower -25dB. Also, at higher frequency, it is confirmed that isolation is improved. Combination of electric field occurs less influence because port1 and port3 is placed horizontally and distribution of electric field is connected to parallel. However, because of combination of electric field, it is more improved from 2dB to 6dB than isolation of port1 and port2. Direct combination occult less effect at port1 and port4 than effect of port2 and port3, it is lower -35dB.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1090-1093
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• 2004

In this paper, a problem of geometrically distorted images is considered. In particular, the paper discusses the detection of a watermark from a photographed image of the watermarked picture. The image is possibly obtained by using a digital camera. This watermark detection problem is made difficult by various geometric distortions added to the original picture through the printing and photographing processes. In particular, the paper focuses on the geometric distortion due to a projective transformation, as part of a camera 3D-to-2D imaging process. It is well-known that a cross ratio of collinear points is invariant under a perspective projection. By exploiting this fact, a projective-invariant digital watermarking technique is developed. By detecting the picture's corners, and the image center point at the intersection of two main diagonal lines, predefined cross ratios are used to compute the watermark embedded locations. From those identified embedding pixel locations, a watermark can be detected by performing a correlation between a watermark pattern and the image over those pixels. The proposed method does not require an inverse transformation on the distorted image, thus simplifying the detection process. Performance of the proposed method has been analyzed through computer experiments

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.331-341
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• 2019

With the popularity of sensor-rich environments, smartphones have become one of the major platforms for obtaining and sharing information. Since it is difficult to utilize GNSS (Global Navigation Satellite System) inside the area with many buildings, the localization of smartphone in this case is considered as a challenging task. To resolve problem of localization using smartphone a four step image-based localization method and procedure is proposed. To improve the localization accuracy of smartphone datasets, MMS (Mobile Mapping System) and Google Street View were utilized. In our approach first, the searching for candidate matching image is performed by the query image of smartphone's using GNSS observation. Second, the SURF (Speed-Up Robust Features) image matching between the smartphone image and reference dataset is done and the wrong matching points are eliminated. Third, the geometric transformation is performed using the matching points with 2D affine transformation. Finally, the smartphone location and attitude estimation are done by PnP (Perspective-n-Point) algorithm. The location of smartphone GNSS observation is improved from the original 10.204m to a mean error of 3.575m. The attitude estimation is lower than 25 degrees from the 92.4% of the adjsuted images with an average of 5.1973 degrees.

• Journal of Practical Engineering Education
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• v.15 no.3
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• pp.635-640
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• 2023

Creating New Value Through Digital Transformation Across Industries Worldwide: A Focus on Transitioning from CAD to BIM Design in the Construction Sector with the Implementation of Mandatory BIM Design by 2025 by the Ministry of Land, Infrastructure, and Transport in South Korea. Challenges and Proposed Methodology for Enhancing Efficiency in BIM Design in the Civil Engineering Field of Underground Infrastructure, and Nurturing BIM Design Experts.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.4
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• pp.186-192
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• 2021

Recently, the demand for more precise and demand-oriented customized spatial information is increasing due to the 4th industrial revolution. In particular, the use of 3D spatial information and digital twins which based on spatial information, and research for solving social problems in cities by using such information are continuously conducted. Globally, non-face-to-face services are increasing due to COVID-19, and the national policy direction is also rapidly progressing digital transformation, digitization and virtualization of the Korean version of the New Deal, which means that 3D spatial information has become an important factor to support it. In this study, physical objects for cities defined by world organizations such as ISO, OGC, and ITU were selected and the target of the 3D object model was limited to buildings. Based on CityGML2.0, the data collected using a drone suitable for building a 3D model of a small area is selected to be updated through road name address and building ledger, which are administrative information related to this, and LoD2.5 data is constructed and urban space. It was intended to suggest an object update method for a 3D building among data.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.168-175
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• 2013

This paper presents compact dual-band WLAN filter and filter module. They were developed by embedding all of the passive lumped elements into a LTCC substrate. In order to reduce the size/volume of the filter and avoid EM parasitic couplings between the passive elements, the proposed filter was designed using a 3rd order Chebyshev circuit topology and J-inverter transformation technology. The 3rd order Chebyshev bandpass filter was firstly designed for the band-selection of the 802.11b and was then transformed using finite transmission zeros technologies. Finally, the dual-band filter was realized by adding two notch resonators to the 802.11b filter circuit for the band-selection of the 802.11a/g. The maximum insertion losses in the lower and higher passbands were better than 2.0 and 1.3 dB with minimum return losses of 15 and 14 dB, respectively. Furthermore, the filter was integrated with a diplexer to clearly split the signals between 2 and 5 GHz. The maximum insertion and minimum return losses of the fabricated module were 2.2 and 14 dB at 2.4 - 2.5 GHz, and 1.6 and 19 dB at 5.15 - 5.85 GHz, respectively. The overall volume of the fabricated filter was $2.7{\times}2.3{\times}0.59mm^3$.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.537-543
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• 2015

In Korea, the use of world geodetic system(WGS) has been mandated in year 2010. Accordingly, the national geographic information institute(NGIS) provides the digital maps according to the WGS. Nevertheless, most of the digital geological maps are still based on the Tokyo Datum(TD). Therefore, users should conduct 2D/3D geological spatial analysis after converting the coordinates of digital geological maps to WGS. The conversion process is often tedious and troublesome for certain users. Therefore, in this study, the method to transform coordinate from TD to WGS using ArcToolbox is introduced for users not familiar with the process. For a better appreciation, the Chungju and Hwanggang-ri digital sheets of 1:50,000 scale was chosen as an example. Here, Chungju and Hwanggang-ri sheets were defined based on the TD-central origin and TD-east origin, respectively. The two sheets were merged after the transformation of TD-east origin of Hwanggang-ri to the TD-central origin, and eventually transformed to WGS-central origin. The merged map was found to match exactly with the digital map(Daeso 367041). The problem of coordinate determination in previous digital geological maps was solved effectively. The proposed method is believed to be helpful to 2D/3D geological spatial analysis of various geological thematic maps.