• Korean Journal of Mathematics
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• v.26 no.1
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• pp.87-101
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• 2018

The purpose of this paper is to define a new class of hyperholomorphic functions spaces, which will be called $F^{\alpha}_{{\omega},G}$(p, q, s) type spaces. For this class, we characterize hyperholomorphic weighted ${\alpha}$-Bloch functions by functions belonging to $F^{\alpha}_{{\omega},G}$(p, q, s) spaces under some mild conditions. Moreover, we give some essential properties for the extended weighted little ${\alpha}$-Bloch spaces. Also, we give the characterization for the hyperholomorphic weighted Bloch space by the integral norms of $F^{\alpha}_{{\omega},G}$(p, q, s) spaces of hyperholomorphic functions. Finally, we will give the relation between the hyperholomorphic ${\mathcal{B}}^{\alpha}_{{\omega},0}$ type spaces and the hyperholomorphic valued-functions space $F^{\alpha}_{{\omega},G}$(p, q, s).

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.313-318
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• 2002

A robust attitude controller using Lyapunov redesign technique for spacecraft is proposed. In this controller, qua- ternion feedback is considered to have the attitude maneuver capability very close to the eigen-axis rotation. The controller consists of three parts: the nominal feedback parts which is a PD-type controller for the nominal system without uncertainties, the additional term compensating for the gyroscopic motion, and the third part for ensuring robustness to uncertainties. Lyapunov stability criteria is applied to stability analysis. The performance of the proposed controller is demonstrated via computer simulation.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.147-156
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• 2001

In this paper, a robust attitude control scheme based on Eigenaxis rotation for the spacecraft is proposed. Eigenaxis rotation transforms the attitude of spacecraft to the shortest path and is represented by quaternion. The control law consists of PD-type control part for the nominal system and the robust control part for compensating inertia uncertainty. For the proposed controller, stability analysis is performed and the performance is shown via computer simulation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.141-149
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• 2005

This paper deals with formulations of the energy equilibrium equation by an introduction of the algebraic description, quarternion, which meets conservations of system energy for the equation of motion. Then the equation is discretized to analyze the dynamits analysis of flexible multibody systems in such a way that the work done by the constrained force completely is eliminated. Meanwhile, Rodrigues parameters we used to express the finite rotation lot the proposed method. This method lot the initial essential step to a guarantee of developments of the 3D dynamical problem provides unconditionally stable conditions for the nonlinear problems through the numerical examples.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.47-54
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• 2013

In this paper, we present an inertial sensor-based motion capturing system to measure and analyze whole body movements. This system implements a wireless AHRS(attitude heading reference system) we developed using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. We performed 3D motion capture using the quaternion data calculated. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE of 2.56 degree. The results suggest that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limbs or gait analysis during the post-stroke recovery process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.609-618
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• 2015

This paper discusses the attitude determination of the CNUSAIL-1 cube-satellite. The primary mission of the CNUSAIL-1 is sail deployment and operation in low Earth orbit, and the secondary mission is to look into influence of the sail deployment on satellite attitude and orbit. The attitude determination strategy is proposed depending on three mission phases, and its performance and applicability are verified through numerical simulations. This study considers the following sensors: Sun sensors and a three-axis magnetometer as attitude reference sensors, and a three-axis MEMS gyroscope as an inertial attitude sensor. Because sensors used for cube satellites have relatively low performances and worse noise characteristics, an Extended Kalman filter (EKF) is applied to attitude determination. Additionally, it has the merits to deal with the Gaussian noises and to predict the attitude even with no measurements from reference attitude sensors, especially in the eclipse of the cube satellite. The performance of the EKF is compared to a deterministic attitude determination technique, QUEST(QUaternion ESTimation).

• Journal of Elementary Mathematics Education in Korea
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• v.17 no.1
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• pp.129-142
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• 2013

The purpose of this study was to investigate the typical characteristics of mathematics education of Japan. In order to achieve this goal, we focused the journal 'Arithmetic Education' from 2007 to 2011. This journal has published by the Japan Society of Mathematical Education and 6 issues each year. A total of 133 articles related with mathematics education were analyzed. The typical characteristics of Japan's research for mathematics education were as follows: The number of single author of article were 98 cases (74%), and those of two co-authors were 21 cases (16%). There are some unusual research topic for mathematics education such as 'combined class'. 'cultural pluralism' and 'mathematics learning disabled children'. The articles 'statistical methods related to educational evaluation', 'statistical analysis for educational evaluation' and 'the relationship between number and quantity on the quaternion number' are very interesting results to the readers who know the basics of statistics and algebra. We may find many researcher who majored pure mathematics in the University of Educations in Korea. So we hope that they may write the paper which combine the pure mathematics and mathematics education. The education survey conducted by the policy is actually very meaningful. If the researcher can connect these surveys to the field of education, then the readers can see a nice paper in the journal of elementary mathematics education in Korea. Finally, it is very difficult to find that counterstatement paper for the results of the other's.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1197-1199
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• 2003

ROCSAT-2 mission is to daily image over Taiwan and the surrounding area for disaster monitoring, land use, and ocean surveillance during the 5-year mission lifetime. The satellite will be launched in December 2003 into its mission orbit, which is selected as a 14 rev/day repetitive Sun-synchronous orbit descending over (120 deg E, 24 deg N) and 9:45 a.m. over the equator with the minimum eccentricity. National Space Program Office (NSPO) is developing a ROCSAT-2 Image Processing System (IPS), which aims to provide real-time high quality image data for ROCSAT-2 mission. A simulated ROCSAT-2 image, based on Level 1B QuickBird Data, is generated for IPS verification. The test image is comprised of one panchromatic data and four multispectral data. The qualification process consists of four procedures: (a) QuickBird image processing, (b) generation of simulated ROCSAT-2 image in Generic Raw Level Data (GERALD) format, (c) ROCSAT-2 image processing, and (d) geometric error analysis. QuickBird standard photogrammetric parameters of a camera that models the imaging and optical system is used to calculate the latitude and longitude of each line and sample. The backward (inverse model) approach is applied to find the relationship between geodetic coordinate system (latitude, longitude) and image coordinate system (line, sample). The bilinear resampling method is used to generate the test image. Ground control points are used to evaluate the error for data processing. The data processing contains various coordinate system transformations using attitude quaternion and orbit elements. Through the qualification test process, it is verified that the IPS is capable of handling high-resolution image data with the accuracy of Level 2 processing within 500 m.