• The Journal of Korea Robotics Society
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• v.19 no.2
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• pp.188-195
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• 2024

This paper proposes a photorealistic real-time dense 3D mapping system that utilizes a neural network-based image enhancement method and mesh-based map representation. Due to the characteristics of the underwater environment, where problems such as hazing and low contrast occur, it is hard to apply conventional simultaneous localization and mapping (SLAM) methods. At the same time, the behavior of Autonomous Underwater Vehicle (AUV) is computationally constrained. In this paper, we utilize a neural network-based image enhancement method to improve pose estimation and mapping quality and apply a sliding window-based mesh expansion method to enable lightweight, fast, and photorealistic mapping. To validate our results, we utilize real-world and indoor synthetic datasets. We performed qualitative validation with the real-world dataset and quantitative validation by modeling images from the indoor synthetic dataset as underwater scenes.

• Korean Journal of Computational Design and Engineering
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• v.4 no.2
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• pp.79-86
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• 1999

A general approach to automatic generation of triangular meshes on three-dimensional surfaces is presented in this paper. The approach, developed with emphasis on program generality and interface with CAD/CAM systems, is based on the double mapping method and the looping method. The double mapping method is introduced and anew splitting scheme is proposed for the looping method employed for triangular mesh generation on the parametric domain. Several application examples are given.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.417-424
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• 2001

This paper proposes new symbol mapping method that can enhance the performance of trellis coded M-ary PSK compared with conventional symbol mapping methods in AWGN environment. Since the basic criteria of TCM design is Maximum Euclidean distance in AWGN, conventional symbol mapping method keep this basic criteria. In this paper, proposed new symbol mapping method uses both Euclidean distance and Hamming distance to design, while conventional methods make use of only optimal Euclidean distance. New symbol mapping method show the better BER performance than the other through computer simulation and error equations.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.15-27
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• 2003

Recently, the volume of data is increasing rapidly in server for multimedia service, according to development of multimedia application environment. In recent research for storage technology the technology like of the SAN(Storage Area Network) advantages in scalibility of storage devices, and can read data from multiple disk arrays through RAID 0, 5. The RAID 0 and 5 translate to logical address to physical address using equation, but in case of adding disks at the system with equation -based mapping, the problem that we must rearrange the whole data in the previous disks happens. We use the mapping table to solve this problem in recent, but we can not load the whole mapping table in main memory because it occupies too large space. Therefore the extra I/Os are demanded to evaluate real physical address of data, so total performance of the system is degraded. In this paper, we propose the mapping method that supports the scalibility in RAID 0 or 5 system. The proposing method applies small metadata, so- called SZIT and simple equation, so it is possible that we make translate logical address to physical address rapidly and it is scalable in disk extending simultaneously Our suggesting method, if we add disks to the striping system for expanding of storage capacity, has an advantage of never stop service. So, SZlT-based mapping method can do online-disk-expanding in real-time service.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.1
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• pp.93-101
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• 2010

Currently lots of studies to solve meta-data interoperability in between schema attributes are conducted. But the accuracy in previous schema mapping studies is low since the studies just use the similarity in between attributes. So the studies are not suitable for the schema mapping such as document conversion, system integration, etc. In this paper, we propose a method which can conduct the schema mapping interactively using frequent pattern mining. The method can conduct more accurate mapping process because the method use the description element which is an element among each schema element for the metadata standard. A performance study has been conducted to compare the accuracy performance of the method using metadata standards.

• Journal of Powder Materials
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• v.29 no.4
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• pp.303-308
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• 2022

The plastic deformation behavior of additively manufactured anisotropic structures are analyzed using the finite element method (FEM). Hill's quadratic anisotropic yield function is used, and a modified return-mapping method based on dual potential is presented. The plane stress biaxial loading condition is considered to investigate the number of iterations required for the convergence of the Newton-Raphson method during plastic deformation analysis. In this study, incompressible plastic deformation is considered, and the associated flow rule is assumed. The modified return-mapping method is implemented using the ABAQUS UMAT subroutine and effective in reducing the number of iterations in the Newton-Raphson method. The anisotropic tensile behavior is computed using the 3-dimensional FEM for two tensile specimens manufactured along orthogonal additive directions.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.137-140
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• 2021

High dynamic range (HDR) technology has been drawing attention in the field of imaging and consumer entertainment. As tools for capturing and creating HDR contents, encoding, and transmission evolve to support HDR formats, various display capabilities are being developed and increased. Hence, there is need for remapping native HDR imagery for display on lower quality legacy standard dynamic range (SDR) displays. This operation is referred to as tone mapping. In this paper, we present a sectional tone mapping method by Lenzen, and expand upon a tone mapping approach to improve temporal stability while maintaining picture quality. Compared to the existing block-based sectional tone mapping, our method uses the edge awareness-based tone mapping. We estimate the performance of the objective metric on temporal flickering. The experimental result shows that the algorithm maintains a smoother relationship between the output luminance values, and this reveals success in reducing halos and improving temporal stability with adopted edge aware filtering.

• Earthquakes and Structures
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• v.3 no.1
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• pp.59-81
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• 2012

A ductility inverse-mapping method for SDOF systems including passive dampers is proposed which enables one to find the maximum acceleration of ground motion for the prescribed maximum response deformation. In the conventional capacity spectrum method, the maximum response deformation is computed through iterative procedures for the prescribed maximum acceleration of ground motion. This is because the equivalent linear model for response evaluation is described in terms of unknown maximum deformation. While successive calculations are needed, no numerically unstable iterative procedure is required in the proposed method. This ductility inverse-mapping method is applied to an SDOF model of bilinear hysteresis. The SDOF models without and with passive dampers (viscous, viscoelastic and hysteretic dampers) are taken into account to investigate the effectiveness of passive dampers for seismic retrofitting of building structures. Since the maximum response deformation is the principal parameter and specified sequentially, the proposed ductility inverse-mapping method is suitable for the implementation of the performance-based design.

• 한국전산유체공학회:학술대회논문집
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• 1995.10a
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• pp.82-89
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• 1995

In the present paper, a method of nearly orthogonal grid generation in an arbitrary simply-connected 3D domain will be presented. The method is a new direct and non-iterative scheme based on the concept of the decomposition of the global orthogonal transformation into consecutive mapping of a conformal mapping and an auxiliary orthogonal mapping, which was suggested by King and Leal [4]. In our numerical scheme. Kang and Leal's method is extended from 2D problems to 3D problems while the advantage of the non-iterative algorithm is maintained. The essence of the present mapping method is that an iterative scheme can be avoided by introducing a preliminary step. This preliminary step corresponds to a conformal map and is based on the boundary element method(BEM). This scheme is applied to generate several nearly-orthogonal grid systems which are orthogonal at boundaries.

• Advances in robotics research
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• v.2 no.1
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• pp.45-57
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• 2018

Even though the popularity of projection mapping continues to increase and it is being implemented in more and more settings, most current projection mapping systems are limited to special purposes, such as outdoor events, live theater and musical performances. This lack of versatility arises from the large number of projectors needed and their proper calibration. Furthermore, we cannot change the positions and poses of projectors, or their projection targets, after the projectors have been calibrated. To overcome these problems, we propose a projection mapping method using a projector robot that can perform projection mapping in more general or ubiquitous situations, such as shopping malls. We can estimate a projector's position and pose with the robot's self-localization sensors, but the accuracy of this approach remains inadequate for projection mapping. Consequently, the proposed method solves this problem by combining self-localization by robot sensors with position and pose estimation of projection targets based on a 3D model. We first obtain the projection target's 3D model and then use it to accurately estimate the target's position and pose and thus achieve accurate projection mapping with a projector robot. In addition, our proposed method performs accurate projection mapping even after a projection target has been moved, which often occur in shopping malls. In this paper, we employ Ubiquitous Display (UD), which we are researching as a projector robot, to experimentally evaluate the effectiveness of the proposed method.