• Journal of Korea Game Society
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• v.10 no.6
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• pp.57-65
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• 2010

In this paper, mobility performance indices are proposed which may be used to estimate characteristics of output velocity space in six-degree-of-freedom parallel mechanism. In order for manipulability and condition number to not suffer from lack of the physical meaning due to dimensional inhomogeneity, output space is partitioned into translational velocity space and rotational velocity space, respectively. In each space, mobility ellipsoids corresponding to unit input space are defined and two types of mobility performance in translational velocity spaces indices are derived. Two types of mobility performance in rotational velocity spaces indices are derived.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.439-441
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• 2002

The aim of this study is to reconstruct the 3D target volume from multiple projection images. It was assumed that we were already aware of the target position exactly, and all processes were performed in Target Coordinates whose origin was the center of the target. We used six projections: two projections were used to make a Reconstruction Box and four projections were for image acquisition. Reconstruction Box was made up of voxels of 3D matrix. Projection images were transformed into 3D volume in this virtual box using geometrical based back-projection method. Algorithm was applied to an ellipsoid model and horse-shoe shaped model. Projection images were created using C program language by geometrical method and reconstruction was also accomplished using C program language and Matlab(The Mathwork Inc., USA). For ellipsoid model, reconstructed volume was slightly overestimated but target shape and position was proved to be correct. For horse-shoe shaped model, reconstructed volume was somewhat different from original target model but there was a considerable improvement in target volume determination.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.309-318
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• 2001

In this paper, we describe methods that analyze a human gesture. A human interface(HI) system for analyzing gesture extracts the head and hand regions after taking image sequence of and operators continuous behavior using CCD cameras. As gestures are accomplished with operators head and hands motion, we extract the head and hand regions to analyze gestures and calculate geometrical information of extracted skin regions. The analysis of head motion is possible by obtaining the face direction. We assume that head is ellipsoid with 3D coordinates to locate the face features likes eyes, nose and mouth on its surface. If was know the center of feature points, the angle of the center in the ellipsoid is the direction of the face. The hand region obtained from preprocessing is able to include hands as well as arms. For extracting only the hand region from preprocessing, we should find the wrist line to divide the hand and arm regions. After distinguishing the hand region by the wrist line, we model the hand region as an ellipse for the analysis of hand data. Also, the finger part is represented as a long and narrow shape. We extract hand information such as size, position, and shape.

• Applied Microscopy
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• v.27 no.2
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• pp.155-163
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• 1997

Ultrastructural and histochemical studies were carried out on the prostate gland of a Korean slug (Incilaria fruhstorferi) with light and electron microscopes. The results are as follows. The endothelial tissue of the prostate gland is constituted with tall and narrow ciliated columnar cells, irregularly shaped cells and gland cells in which are included the elongated oval or ellipsoid nucleus those are surrounded by curved membrane. The endothelial tissue of the prostate gland is composed by type-A, B, C and type-D gland cells, and the glanules of type-A, B, and D gland cells are certified to neutral mucopolysaccharide because are related by PAS-alcian blue (pH 2.5) , but the other hand type-C gland cell is only weakly reacted to PAS, but strongly reacted by Million reaction. The glanules of type-A gland cell are small size (about $0.4{\mu}m$) and are seen high electron density, but the glanules of type-B gland cell are large size (about $0.7{\mu}m$) and glanule density is same type-A glanules. Long ellipsoid type-C gland cell contained round nucleus which is well developed beterochromatin in, and that small oval glanules (size, about $0.9{\mu}m$) of moderate high electron density which are formed a group of large glanule together with $4\sim5ea$, but type-D gland cell possessed round small nucleus are seen high electron dense glanules (size, $0.8{\mu}m$).

• Communications for Statistical Applications and Methods
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• v.18 no.6
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• pp.761-770
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• 2011

Robust principal components regression is suggested to deal with both the multicollinearity and outlier problem. A main aspect of the robust principal components regression is the selection of an optimal set of principal components. Instead of the eigenvalue of the sample covariance matrix, a selection criterion is developed based on the condition index of the minimum volume ellipsoid estimator which is highly robust against leverage points. In addition, the least trimmed squares estimation is employed to cope with regression outliers. Monte Carlo simulation results indicate that the proposed criterion is superior to existing ones.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.1
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• pp.13-23
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• 2020

In this paper, we propose a quantization parameter determination method for face depth image encoding in order to minimize an impact on a face recognition accuracy. When a face depth image is compressed through quantization in H.264/AVC, differential quantization parameters are assigned according to an accuracy of ellipsoid modeling prediction and an importance degree of a unit block in extracting facial features. The simulation results show that the face recognition success rates are improved by up to 6% at the same compression rates through the proposed compression rate determination method.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.625-627
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• 2003

In this study, the Global Positioning System (GPS) data collected by the GPS receivers that were established as continuously operating reference stations by Central Weather Bureau and Industrial Technology Research Institute of Taiwan are utilized to investigate the impact of atmospheric water vapor on GPS positioning determination. The surface meteorological measurements that were concurrently acquired by instruments co-located with the GPS receivers include temperature, pressure and humidity data. To obtain the influence of the baseline length on the proposed impact study, four baselines are considered according to the locations of the permanent GPS sites. The length of the shorter baseline is about 66km, while the longer is about 118 km. The results from the studies associated with different baseline lengths and ellipsoid height were compared for the cases with and without a priori knowledge of surface meteorological measurements. The finding based on 66 days measurements is that the surface meteorological measurements have a significant impact on the positioning determination for the longer baseline case. The associated daily maximum differences are 1.1 cm and 1.4 cm for the baseline and ellipsoid height respectively. The corresponding biases are -8.1 mm in length and -7.3 mm in el lipsoid height.

• Korean Journal of Remote Sensing
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• v.14 no.1
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• pp.69-82
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• 1998

SAR imagery can overcome the limitations of electro-optical sensor imagery and provide us Information which plays a supplementary role. But it is necessary to remove a variety of geometric errors in SAR imagery. An accurate geometric correction of SAR imagery is not easy task to achieve, though some techniques and theories are introduced. We also have difficulties such as transformation problem between 'International' ellipsoid in Radarsat system and 'Bessel' ellipsoid. Two widely used correction method, one is made by simulated image, and the other by collinearity equation, usually use DEM. In this study, the merits and demerits of geocoding methods respectively and the effective method for Korean terrain were found.

• Tunnel and Underground Space
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• v.30 no.6
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• pp.551-558
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• 2020

This note presents the calculation of nominal area for rock core specimen under direct shear testing condition. The initial nominal area was assumed as ellipsoid, and the equations for calculating the nominal area are derived. The normalized shear displacement and normalized nominal area have an identical relationship regardless of the ellipsoid shape. New testing constants and the generalized method were suggested to calculate the decrease of the nominal area. The method was applied to calculate the direct shear testing data and the changes of result were discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.531-539
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• 2011

It has been widely acknowledged that climate system associated with extreme rainfall events was difficult to understand and extreme rainfall simulation in climate model was more difficult. This study developed a new model for extracting rainfall filed associated with extreme events as a way to characterize large scale climate system. Main interests are to derive location, size and direction of the rainfall field and this study developed an algorithm to extract the above characteristics from global climate data set. This study mainly utilized specific humidity and wind vectors driven by NCEP reanalysis data to define the rainfall field. Geometric first and second moments have been extensively employed in defining the rainfall field in selected zone, and an ellipsoid based model were finally introduced. The proposed geometric moments based ellipsoid model works equally well with regularly and irregularly distributed synthetic grid data. Finally, the proposed model was applied to space-time real rainfall filed. It was found that location, size and direction of the rainfall field was successfully extracted.