• 대한수학회보
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• 제49권3호
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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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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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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.

• 호남수학학술지
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• 제34권3호
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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.

• 한국측량학회지
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• 제17권3호
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• pp.265-272
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• 1999

현재 우리나라의 수치지도에서는 동경원점계에 의한 Bessel타원체 좌표계를 사용하고 있으므로 새로운 지구중심좌표계(ITRF)에 의한 GRS80타원체 좌표계와는 상당한 차이가 발생하게 된다. 본 연구에서는 새로운 좌표계의 도입에 따른 지도좌표계의 전환에 대비할 수 있도록 하기 위하여 두 체계간의 좌표차와 도엽체계에 대한 특성과 경향을 파악하고, 두 좌표계간의 지도좌표계 전환모듈을 제시하였다.

• Mycobiology
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• 제51권4호
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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.

• 한국통신학회논문지
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• 제32권6C호
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• pp.572-578
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• 2007

영상 회의 시스템에서는 현실감을 높이기 위하여 대화 상대방과 시선을 맞추는 eye contact을 만들어 주는 것이 중요하다. 이를 위하여 영상 기반 방법과 모델 기반 방법 등의 시점합성기법이 연구되고 있다. 전자는 계산이 간단하나 부정확하고, 후자는 잡음에 강하고 정확한 영상을 만들어 내지만 시간이 많이 걸리는 단점이 있다. 본 논문에서는 얼굴 영상을 타원으로 근사화시키고 이를 3차원 공간에서 타원체로 모델링하여 임의의 가상 카메라의 위치에서 영상을 합성하는 방법을 제안하였다. 여러 가지 실험을 통하여 제안한 방법이 계산량이 적으면서도 성능이 우수함을 입증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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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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• 제2권2호
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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.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2018년도 하계학술대회
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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.

• 식물분류학회지
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• 제53권1호
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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.