• Bulletin of the Korean Mathematical Society
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• v.49 no.3
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• pp.465-479
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• 2012

For $0<p{\leq}{\infty}$ and a convex body $K$ in $\mathbb{R}^n$, Lutwak, Yang and Zhang defined the concept of dual $L_p$-centroid body ${\Gamma}_{-p}K$ and $L_p$-John ellipsoid $E_pK$. In this paper, we prove the following two results: (i) For any origin-symmetric convex body $K$, there exist an ellipsoid $E$ and a parallelotope $P$ such that for $1{\leq}p{\leq}2$ and $0<q{\leq}{\infty}$, $E_qE{\supseteq}{\Gamma}_{-p}K{\supseteq}(nc_{n-2,p})^{-\frac{1}{p}}E_qP$ and $V(E)=V(K)=V(P)$; For $2{\leq}p{\leq}{\infty}$ and $0<q{\leq}{\infty}$, $2^{-1}{\omega_n}^{\frac{1}{n}}E_qE{\subseteq}{\Gamma}_{-p}K{\subseteq}{2\omega_n}^{-\frac{1}{n}}(nc_{n-2,p})^{-\frac{1}{p}}E_qP$ and $V(E)=V(K)=V(P)$. (ii) For any convex body $K$ whose John point is at the origin, there exists a simplex $T$ such that for $1{\leq}p{\leq}{\infty}$ and $0<q{\leq}{\infty}$, ${\alpha}n(nc_{n-2,p})^{-\frac{1}{p}}E_qT{\supseteq}{\Gamma}_{-p}K{\supseteq}(nc_{n-2,p})^{-\frac{1}{p}}E_qT$ and $V(K)=V(T)$.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1790-1795
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• 1991

The optimal load distribution for two cooperating robots is studied in this paper, and a new solution approach utilizing force ellipsoid is proposed. The load distribution problem is formulated as a nonlinear optimization problem with a quadratic cost function. The limit on instantaneous power is considered in the problem formulation as the joint torque constraints. The optimal solution minimizing energy consumption is obtained using the concept of force ellipsoid and the nonlinear optimization theory. The force ellipsoid provides a useful geometrical insight into the load distribution problem. Despite the presence of the joint torque constraints, the optimal solution is obtained almost as a closed form, in which the joint torques are given in terms of a single scalar parameter that can be obtained numerically by solving a scalar equation.

• Honam Mathematical Journal
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• v.34 no.3
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• pp.403-408
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• 2012

In this paper, we prove that if K is a convex body in $E^n$ and $E_i$ and $E_o$ are inscribed ellipsoid and circumscribed ellipsoid of K respectively with ${\alpha}E_i=E_o$, then $\[({\alpha})^{\frac{n}{p}+1}\]^n{\omega}^2_n{\geq}V(K)V({\Gamma}^{\ast}_pK){\geq}\[(\frac{1}{\alpha})^{\frac{n}{p}+1}\]^n{\omega}^2_n$. Lutwak and Zhang[6] proved that if K is a convex body, ${\omega}^2_n=V(K)V({\Gamma}_pK)$ if and only if K is an ellipsoid. Our inequality provides very elementary proof for their result and this in turn gives a lower bound of the volume product for the sets of constant width.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.3
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• pp.265-272
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• 1999

The map coordinate systems of Korea, based on the Bessel 1841 ellipsoid with Tokyo Datum, applied in digital mapping. So, the new geocentric system have some coordinate differences compared to GRS80 ellipsoid with the International Terrestrial Reference Frame(ITRF). Therefore, map transition procedures are needed to establish for the new coordinate system. In this paper, characteristics and tendencies about coordinate differences and map tiles systems are investigated and modules for the map coordinate transformations between two systems are developed and simulated.

• Mycobiology
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• v.51 no.4
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• pp.210-215
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• 2023

The aim of this study was to characterize a new fungal species, Acremonium conglutinatum, isolated from air samples collected in Wando, South Korea. Phylogenetic analysis based on the internal transcribed spacer and large subunit regions revealed its unique position within the genus Acremonium. The isolated strain displayed distinct morphological characteristics, including ellipsoid or bent-ellipsoid conidia formed in clusters on the phialides. These features differentiate the new species from closely related species within the genus. This study describes the morphological and molecular characteristics of A. conglutinatum and emphasizes its phylogenetic relationships with other Acremonium spp. The identification of this novel species contributes to our understanding of the diversity and ecological role of Acremonium.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6C
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• pp.572-578
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• 2007

To establish eye contact in video teleconferencing, it is necessary to synthesize a front view image by viewpoint interpolation. We can find the viewing direction of a user, and interpolate an image seen from that viewpoint, which will result in a face image observed from the front. There are two categories of previous research: image based method and model based method. The former is simple to calculate, however, it shows limited performance for complex objects. And the latter is robust to noise while it is computationally expensive. We propose to approximate face images as ellipses and match them to build an ellipsoid and then synthesize a new image from a given virtual camera position. We show that it is simple and robust from various experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.107.5-107
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• 2002

In this paper, a kinematic optimal design of a new paralleltype rolling mill based upon two Stewart platforms manipulator is investigated. The objective of this new parallel-type rolling mill is to permit an integrated control of the strip thickness, strip shape, pair crossing angle, uniform wear of the rolls, and tension of the strip. A manipulability measure, as the ratio of the manipulability ellipsoid volume and the condition number of a split Jacobian matrix, is defined. Two kinematic parameters, the radius of the base and the angle between two neighboring joints, are optimally designed by maximizing the global manipulability measure in the entire workspace.

• International Journal of Control, Automation, and Systems
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• v.2 no.2
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• pp.238-246
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• 2004

In displaying a virtual wall using a passive haptic device equipped with passive actuators such as electric brakes, unsmooth motion frequently occurs. This undesirable behavior is attributed to time delay due to slowness in the virtual environment update and force approximation due to the inability of a brake to generate torque in arbitrary directions. In this paper a new control scheme called direct control is proposed to achieve smooth display on the wall-following task with a passive haptic device. In direct control, brakes are controlled so that the normal component of a resultant force at the end-effector vanishes, based on the force analysis at the end-effector of the passive haptic device using the passive FME (Force Manipulability Ellipsoid). Various experiments have been conducted to verify the validity of the direct control scheme with a 2-link passive haptic system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.116-119
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• 2018

In this paper, we propose a new single-image dehazing method. The proposed method constructs color ellipsoids that are statistically fitted to haze pixel clusters in RGB space and then calculates the transmission values through color ellipsoid geometry. The transmission values generated by the proposed method maximize the contrast of dehazed pixels, while preventing over-saturated pixels. The values are also statistically robust because they are calculated from the averages of the haze pixel values. Furthermore, rather than apply a highly complex refinement process to reduce halo or unnatural artifacts, we embed a fuzzy segmentation process into the construction of the color ellipsoid so that the proposed method simultaneously executes the transmission calculation and the refinement process. The results of an experimental performance evaluation verify that compared to prevailing dehazing methods the proposed method performs effectively across a wide range of haze and noise levels without causing any visible artifacts. Moreover, the relatively low complexity of the proposed method will facilitate its real-time applications.

• Korean Journal of Plant Taxonomy
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• v.53 no.1
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• pp.25-31
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• 2023

Glycosmis kanburiensis (Rutaceae) from Kanchanaburi Province, southwestern Thailand is described as a new species. It is similar to G. esquirolii (H. Lév.) Tanaka in its dendriform habit, terminal inflorescences, and large leaflets, but several easily recognizable differences in floral features, including triangular sepals with rust-colored indumentum (vs. broadly ovate villose sepals), globose, glabrous (vs. subglobose, villosus) ovary, cylindrical and attenuate (vs. stout) style, and ellipsoid (vs. globose) fruit. A taxonomic description, illustration, photographs, geographical distribution, ecological data, and conservation status are provided.