• Journal of Positioning, Navigation, and Timing
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• v.6 no.1
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• pp.27-33
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• 2017

GPS provides the positioning solution in most areas of the world. However, the position error largely occurs in the urban area due to signal attenuation, signal blockage, and multipath. Although many studies have been carried out to solve this problem, a definite solution has not yet been proposed. Therefore, research is being conducted to solve the vehicle localization problem in the urban environment by converging sensors such as cameras and Light Detection and Ranging (LIDAR). In this paper, the precise vehicle localization using 3D LIDAR (Velodyne HDL-32E) is performed in the urban area. As there are many tall buildings in the urban area and the outer walls of urban buildings consist of planes generally perpendicular to the earth's surface, the outer wall of the building meets at a vertical corner and this vertical corner can be accurately extracted using 3D LIDAR. In this paper, we describe the vertical corner extraction method using 3D LIDAR and perform the precise localization by combining the extracted corner position and GPS/DR information. The driving test was carried out in an about 4.5 km-long section near Teheran-ro, Gangnam. The lateral and longitudinal RMS position errors were 0.146 m and 0.286 m, respectively and showed very accurate localization performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.96-101
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• 2008

Due to improve form accuracy and surface roughness of a aspheric lens core that is made of Ni, the study is carried out on localization about a Subminiature Optics of Proximity and Wide Field of View. The required form accuracy P-V $0.2{\mu}m$ and surface roughness is Ra 10 nm. The design of experiment(DOE) is adopted to find a optimal cutting conditions which are spindle speed, depth of cut, feedrate. Finally, the effects of this study are replacing importation and strengthening competitiveness through the localization of the Subminiature Optics of Proximity and Wide Field of View.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.307-316
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• 2004

This study examined the cause of the wrinkle defect which is frequently encountered in wire rod rolling of low carbon steel$(C0.08\~0.13wt.\%)$. Even a small defect on the surface of rolled bars can easily develop into fatal cracks during cold heading process of low carbon steel, and it is therefore necessary to minimize inherent defects on the surface of hot rolled bars. Hot rolling process of low carbon steel was analyzed to identify the cause of the wrinkle defect in conjunction with FE analysis. The integrated analysis revealed that the wrinkle defect initiated in the first stage of rolling, and it was at the billet edge where severe deformation and drastic temperature drop were present. To elucidate the micro-mechanical mechanism of the wrinkle defect, hot compression tests were carried out at various temperatures and strain rates using Gleeble-3800. The surface profile of the each other compressed specimens was compared, and rough surface lines were observed at relatively low temperatures. Those surface defects can develop into wrinkles during multi-pass rolling. To control the wrinkle defect in rolling, it is necessary to design an adequate caliber which can minimize the loss of ductility, and thereby prevent flow localization. To use the result of this study fur other steels, the quantitative measure of the wrinkle defect and flow localization parameter should be proposed.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2
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• pp.87-96
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• 2005

In matched field processing (MEP), the observed acoustic field data is basically correlated with the replica produced by the modeling. therefore the results of source localization and correlation is limited by the mismatch of the environment and sensor location. In this paper. the effects of mismatch in environment and system on the bias in estimating the source location are investigated in the context of source localization. In the Pekeris waveguide, the simulation shows that the mismatches in environment and system, can cause a significant biases in the source localization and a degradation in MFP correlation. Mismatch caused by uncertainties in array tilt and depth, bottom depth, bottom sound speed, etc. causes degradation in source localization performance.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.577-581
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• 2009

Interactions between the surface and capsid proteins of the hepatitis B virus (HBV) are critical for the assembly of virus particles. In this study, we developed a cell-based method to visualize the interactions between the capsid and surface proteins of HBV. Capsid-GFP, a capsid protein fused to a green fluorescence protein (GFP), forms nucleocapsid-like structures in the cytoplasm of mammalian cells. It relocates to the plasma membranes in cells expressing PH-PreS, a fusion protein consisting of the PreS region of the HBV surface protein and the PH domain of PLC-$\gamma$. Membrane localization of the capsid-GFP in these cells is prevented by an inhibitory peptide that blocks the interaction between the capsid and surface proteins. This dynamic localization of capsid-GFP is applicable for screening compounds that may potentially inhibit or prevent the assembly process of HBV particles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.277-290
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• 2019

The demand for indoor positioning is increasing day by day. However, the widely used positioning methods today cannot satisfy the requirements of the indoor environment in terms of the positioning accuracy and deployment cost. In the existing research domain, the localization algorithm based on three-dimensional space is less accurate, and its robustness is not high. Visible light communication technology (VLC) combines lighting and positioning to reduce the cost of equipment deployment and improve the positioning accuracy. Further, it has become a popular research topic for telecommunication and positioning in the indoor environment. This paper proposes a surface centroid TOA localization algorithm based on the VLC system. The algorithm uses the multiple solutions estimated by the trilateration method to form the intersecting planes of the spheres. Then, it centers the centroid of the surface area as the position of the unknown node. Simulation results show that compared with the traditional TOA positioning algorithm, the average positioning error of the surface centroid TOA algorithm is reduced by 0.3243 cm and the positioning accuracy is improved by 45%. Therefore, the proposed algorithm has better positioning accuracy than the traditional TOA positioning algorithm, and has certain application value.

• Ocean Systems Engineering
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• v.9 no.4
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• pp.391-407
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• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.617-624
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• 2004

This paper describes a new facial feature localization method that uses Adjacent Depth Differences(ADD) in 3D facial surface. In general, human recognize the extent of deepness or shallowness of region relatively, in depth, by comparing the neighboring depth information among regions of an object. The larger the depth difference between regions shows, the easier one can recognize each region. Using this principal, facial feature extraction will be easier, more reliable and speedy. 3D range images are used as input images. And ADD are obtained by differencing two range values, which are separated at a distance coordinate, both in horizontal and vertical directions. ADD and input image are analyzed to extract facial features, then localized a nose region, which is the most prominent feature in 3D facial surface, effectively and accurately.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.27 no.2
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• pp.87-108
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• 2023

This is a review paper on recent development on the spectral theory of the Neumann-Poincaré operator. The topics to be covered are convergence rate of eigenvalues of the Neumann-Poincaré operator and surface localization of the single layer potentials of its eigenfunctions. Study on these topics is motivated by their relations with the cloaking by anomalous localized resonance. We review on this topic as well.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.300-306
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• 2023

A hull-cleaning robot sticks to the surface of a vessel and moves for efficient cleaning. Precise path planning and tracking using the current position is crucial. Many robots rely on the INS algorithm, but errors accumulate. To fix this, GPS, sonar, and USBL are used, though with limitations. Selecting suitable sensors for the surface operation and accurate positioning algorithm are vital. In this study, we developed a robot position estimation algorithm using the structure of a ship. Problems that arise when expanding the 2D position estimation algorithm used in existing wall structures to 3D were evaluated and methods for solving them were proposed. In addition, we aimed to improve performance by deriving singularities that exist in the robot path and proposing an error correction algorithm based on the singularities.