• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.989-992
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• 2004

In general, it is known that walking stability of a quadruped is determined by its COG(Center of Gravity). In this paper, in order to know whether our virtual quadruped robot is applicable to the real quadruped robot, we simulated our virtual model using the data from the real robot‘s walking. We were able to evaluate the stride of quadruped based on direct and inverse kinematics and compared the stride of the simulation with real robot’s it. During the simulation we calculated the COG of the virtual model and evaluated the walking stability of real model.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.135-145
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• 2017

For a polygon P, we consider the centroid $G_0$ of the vertices of P, the centroid $G_1$ of the edges of P and the centroid $G_2$ of the interior of P. When P is a triangle, (1) we always have $G_0=G_2$ and (2) P satisfies $G_1=G_2$ if and only if it is equilateral. For a quadrangle P, one of $G_0=G_2$ and $G_0=G_1$ implies that P is a parallelogram. In this paper, we investigate the relationships between centroids of quadrangles. As a result, we establish some characterizations for rhombi and show that among convex quadrangles whose two diagonals are perpendicular to each other, rhombi and kites are the only ones satisfying $G_1=G_2$. Furthermore, we completely classify such quadrangles.

• Journal of Power System Engineering
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• v.6 no.3
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• pp.42-48
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• 2002

Velocity change of crashed vehicle has been applied to assess the safety of passenger and degree of impact severity widely. In this study, 1 D crash analysis and 2 D crash analysis were performed for velocity change of crashed vehicle with HVE 2D, and factors used for these analysis are weight, C.G, roll resistance, stiffness and brake force which influence on velocity change of crashed vehicle. According to results, the velocity change of crashed vehicle was influenced by weight, center of gravity stiffness and brake force but not roll resistance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.311-314
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• 1995

Biped locomotion can be simply modeled as a linear inverted pendulum mode. This model considers only the CG (center of gravity) of the entire system. But in real biped robot systems, the free-leg motion dynamics is not negligible. So if its dynamics is not considered in designing the reference CG motion, it is badly influence to the ZMP(zero moment point) position of the biped robot walking in the sagittal plane. Therefore, we modeled the biped locomotion similar to the linear inverted pendulum mode but considered the predetermined free-leg dynamics. To verify that the proposed biped locomotion is more stable than the linear inverted pendulum mode, we constructed a biped robot simulator and designed a serco controller to track both the reference motion of the free leg and the reference motion of CG of the biped robot using the computed torque control low. And through simulations, we verified that the proposed walking is better in stability than the one based on the linear inverted pendulum mode.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.65-71
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• 2008

In this paper, we propose a new driving mode control algorithm for a mobile robot based on obstacle detection. The robot has a variable geometry single-tracked mechanism, so it can maximize a contact length with ground for the adaptability to off-road and puesue a stable system due to the lower center of gravity. However this robot system embodied passive type according to operator. In this reason, several problems are detected. So, this research presents a new method of obstacle detection using PSD infrared sensors and translates the variable tracks on the best suited driving mode actively. And experimental results about mentioned are presented.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.4
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• pp.1-11
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• 2008

This research presents a study for the knowledge-based configuration design development of a RC (remote control) helicopter. Parametric design and knowledge based design concepts are introduced for rapid design changes and analyses using commercial CAD software, CATIA(R) Knowledgeware module. It is crucial for RC helicopter design because it enables rapid conceptual design through instant configuration changes. Positions and dimensions of RC helicopter parts were used as design parameters. As an example, positions of CG(center of gravity) points were traced and plotted as the configuration changes. Further research should be performed in areas of user interfaces and web-based multi-user environments instead of using Excel data sheets.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.1
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• pp.1-6
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• 2011

The free-wing tilt-body aircraft is researched in the flight performance characteristics such as short take-off and landing capability, and reduced sensitivity to gust and center of gravity (CG) change. Due to the main wing separating from the fuselage, the high tiltable empennage, and the stub-wing strongly influencing from the propeller wake, the resulting vehicle aerodynamics and flight dynamics are quite different from those of a conventional fixed-wing aircraft. Using the governing flight dynamics model was studied previously, all of speed and body tilt angle is simulated to determine the flight envelope by a non-linear 3-DOF flight simulation analysis. Though flight performance and trimmability are studied, the flight model of free-wing tilt-body aircraft is to reduce the hidden risk and to achieve the successful flight test. It is analyzed the flight characteristics that distinguishes free-wing tilt-body aircraft from the conventional aircraft.

• Journal of Intelligence and Information Systems
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• v.6 no.1
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• pp.65-72
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• 2000

In this paper we propose the new binary image matching algorithm called the Fuzzy logic induced Hausdorff Distance(FHD) for finding the maximally matched image with the query image. The membership histogram is obtained by normalizing the cardinality of the subset with the corresponding radius after obtaining the distribution of the minimum distance computed by the Hausdroff distance between two binary images. in the proposed algorithm, The fuzzy influence method Center of Gravity(COG) is applied to calculate the best matching candidate in the membership function described above. The proposed algorithm shows the excellent results for the face image recognition when the noise is added to the query image as well as for the character recognition.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.81-87
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• 2015

Load master is authorized to be controlled all of loading stuffs for safety of flight such as passenger, baggage, cargo and e.t.c. There are many things are missed even though the weight and balance is the most important process. This study analyzes how the differences of C.G. by among ten load masters of each careers. This study is tested how load-master takes load-control by the respective result based on differences of each practical experiences, gender and a number of certification. In result, all of load masters set C.G. on the stability region. But the practical experience of load master is relative to set better C.G. for economical effectiveness of weight and balance control work.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.18-26
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• 2011

This paper presents a method, Exposure Controlled Temporal Filtering (ECF), applied to visual motion tracking, that can cancel the temporal aliasing of periodic vibrations of cameras and fluctuations in illumination through the control of exposure time. We first present a theoretical analysis of the exposure induced image time integration process and how it samples sensor impingent light that is periodically fluctuating. Based on this analysis we develop a simple method to cancel high frequency vibrations that are temporally aliased onto sampled image sequences and thus to subsequent motion tracking measurements. Simulations and experiments using the 'Center of Gravity' and Normalized Cross-Correlation motion tracking methods were performed on a microscopic motion tracking system to validate the analytical predictions.