• The Journal of the Acoustical Society of Korea
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• v.14 no.2
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• pp.80-91
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• 1995

A theoretical models has been prepared which describes the noise generated by tire/road interaction for the tire structure-borne sound analysis. The model begin with a set of thin shell equations describing the motion of the belt of a radial ply tire, as drived by Bohm('mechanisms of the belted tire', Igeniur-Archiv, XXXV, 1966). Structural quantities required for these equations are derived from material properties of the tire. The rolling shape of a tire is computed from the steady-state limit of these equations. Vibrational response of the tire is treated by the full dependent shell equations. The force input at the tire/road interface is calculated on the basis of tread geometry and distribution of contact patch pressure. Radiation of noise is calculated by a simpson integral. Using the programs, the effect on noise of various tire design variations is computed and discussed. Trends which lead to quiet tire design are identified.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.4
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• pp.359-367
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• 2000

This paper suggests that coefficients models of the Earth's gravitational potential can be used to calculate height anomalies which are then reduced to the geoid undulation to determine more precise geoid undulation. The potential coefficients and modified coefficients of EGM96 and KODEM33 digital elevation model in and around the Korean peninsula were used for this study. The magnitude of height anomaly computed in this study reached 0.025 m and the mean vaule showed -0.015 m. In this study, geometrical geoid undulation was derived from GPS/Leveling data for evaluating the precisely computed geoid undulation. In comparison with geometric and gravimetric geoid undulations, mean value and standard deviation of the differences showed 0.0114 m and 0.2817 m respectively and it showed the improvement of results.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.177-186
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• 2005

In this Paper. we propose vision-based camera localization technique using 3D information which is created by mapping of DEM and mountain image. Typically, image features for localization have drawbacks, it is variable to camera viewpoint and after time information quantify increases . In this paper, we extract invariance features of geometry which is irrelevant to camera viewpoint and estimate camera extrinsic Parameter through accurate corresponding Points matching by Proposed similarity evaluation function and Graham search method we also propose 3D information creation method by using graphic theory and visual clues, The Proposed method has the three following stages; point features invariance vector extraction, 3D information creation, camera extrinsic Parameter estimation. In the experiments, we compare and analyse the proposed method with existing methods to demonstrate the superiority of the proposed methods.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.5
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• pp.562-573
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• 2002

In this paper, we propose a method for measuring the volume of packages for the efficient handling of the packages. Using the geometrical characteristics of the rectangular parallelepiped type objects, the method measures the volume of packages with one camera only in real time. In preprocessing of volume measurement, the method extracts outer lines of the object and then crossing points of the lines as feature points or vertexes. From these cross points(-feature points-), the volume of the package is calculated. Compared to the direct feature extraction, the proposed method shows especially the blurring robust result by using the line for feature extraction. Additionally, the method can get the stable result by considering object's direction. From experimental results, it is demonstrated that this method is very effective for the real time volume measurement of the rectangular parallelepiped.

• The KIPS Transactions:PartA
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• v.10A no.4
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• pp.357-368
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• 2003

Evaluation of shape similarity for 3D models is essential in many areas - medicine, mechanical engineering, molecular biology, etc. Moreover, as 3D models are commonly used on the Web, many researches have been made on the classification and retrieval of 3D models. In this paper, we describe methods for 3D shape representation and major concepts of similarity evaluation, and analyze the key features of recent researches for shape comparison after classifying them into four categories including multi-resolution, topology, 2D image, and statistics based methods. In addition, we evaluated the performance of the reviewed methods by the selected criteria such as uniqueness, robustness, invariance, multi-resolution, efficiency, and comparison scope. Multi-resolution based methods have resulted in decreased computation time for comparison and increased preprocessing time. The methods using geometric and topological information were able to compare more various types of models and were robust to partial shape comparison. 2D image based methods incurred overheads in time and space complexity. Statistics based methods allowed for shape comparison without pose-normalization and showed robustness against affine transformations and noise.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.245-254
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• 2003

Zoom lenses CCD(Charge Coupled Device) cameras have many desirable features but appear to be geometrically unstable and diffcult to calibrate. It is well blown that the zooming camera parameters change with zoom lens position. This paper presents a comparative study of two approaches, namely, DLT(Direct Linear Transformation) introduced by Abdel-Aziz and Karara and the model proposed by Tsai, to evaluate the camera parameters of zoom lenses CCD camera and 3D positioning accuracy. As a result, the accuracy for 3D positioning using Tsai and DLT model is similar in both methods when the set of GCPs and the object are arranged in the same space. However, Tsai model is more stable than DLT in the case that the object is apart from the set of GCPs. Also, the further study for the parameters optimization of conventional DLT is needed to improve accuracy for 3D positioning.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.311-320
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• 2008

A LIDAR can rapidly generate 3D points by densely sampling the surfaces of targets using laser pulses, which has been efficiently utilized to reconstruct 3D models of the targets automatically. Due to this advantage, LIDARs are increasingly applied to the fields of Defense and Security, for examples, being employed to intelligently guided missiles and manned/unmanned reconnaissance planes. For the prior verification of the LIDAR applicability, this study aims at generating simulated LIDAR data. Here, we derived the sensor equation by modelling the geometric relationships between the LIDAR sub-modules, such as GPS, IMU, LS and the systematic errors associated with them. Based on this equation, we developed a program to generate simulated data with the system parameters, the systematic errors, the flight trajectories and attitudes, and the reference terrain model given. This program had been applied to generating simulated LIDAR data for urban areas. By analyzing these simulated data, we verified the accuracy and usefulness of the simulation. The simulator developed in this study will provide economically various test data required for the development of application algorithms and contribute to the optimal establishment of the flight and system parameters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.435-442
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• 2014

In this paper, radar cross section (RCS) analysis program, RACSAN has been developed to predict RCS of complex structures. RACSAN is based on the high frequency range analysis method of Kirchhoff approximation in physical optics (PO). This program can present RCS including multi-bounce effect in complex structures by combination of geometric optics (GO) and PO method. GO method has a concern in the evaluation of the effective area, and PO method is involved in the calculation of RCS for the final effective area that is evaluated by GO method. Comparisons of the predicted results and analytical solutions showed that the developed program could be an effective tool for predicting RCS in complex structures.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.2
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• pp.83-94
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• 2015

Recently, the necessity of spatial data in unaccessible area was challenged to set up various plans and policies for preparing the unification and the cooperative projects between South-North Korea. Therefore, this paper planned to evaluate the possibility of adopting the error tolerance in Geometric correction for 1/5,000 digital topographic mapping, using the PLEIADES images and the TerraSAR GCPs (Ground Control Points). The geometric correction was performed by changing the number and placement of GCPs by GPS (Global Positioning System) surveying, as the optimal placement of 5 GCPs were selected considering the geometric stability and steady rate. The positional accuracy evaluated by the TerraSAR GCPs, which were selected by optimal placement of GCPs. The RMSE in control points were X=±0.64m, Y=±0.46m, Z=±0.28m. While the result of geometric correction for PLEIADES images confirmed that the RMSE in control points were X=±0.34m, Y=±0.27m, Z=±0.11m, the RMSE in check points were X=±0.50m, Y=±0.30m, Z=±0.66m. Through this study, we believe if spatial data can integrate with the PLEIADES images and the optimal TerraSAR GCPs, it will be able to obtain the high-precision spatial data for adopting the regulation of 1/5,000 digital topographic map, which adjusts the computation as well as the error bound.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.213-223
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• 1998

This paper deals with the geoid modelling in and around Korean peninsula referred to Bessel ellipsoid. Several useful data were used to compute precise geoidal heights referred to GRS80 by remove and restore technique and FFT technique was used to evaluate Stokes' integral. All grid point elevations extracted from GTOPO 30 and Bessel coordinates of all grid point were computed through coordinates transformation by applying three transformation parameters. Finally, geoidal heights referred to Bessel ellipsoid were calculated by geometric method. As the results of this study, a precise gravimetric geoid model referred to GRS80 (KOGGDM33) and geoid model referred to Bessel ellipsoid(KOBGDM33) in and around Korean peninsula were developed. KOBGDM33 shows the gradual distribution of geoidal heights from -91.8 m in Yongampo to -39.0 m in the straits of Korea.