• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.1014-1017
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• 1988

Direct-drive robots have excellent features including no backlash, small friction, and high mechanical stiffness. However, dynamic coupling among joints as well as nonlinear effects become more prominent than traditional robots with reducers. Another critical issue is that the robot becomes more sensitive to the change of load. In this paper, we develop a simple current feedback scheme for reducing the influence of dynamic coupling and load sensitivity on the direct-drive robots. The method is implemented on a 2 d.o.f. planar direct-drive robot. Then the validity of the method is demonstrated through experiments.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.399-404
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• 1992

Curved 3D objects represented by range data contain large amounts of information compared with planar objects, but do not have distinct features for matching to those of object models. This makes it difficult to represent and identify a general 3D curved object. This paper introduces a new approach to representing and finding a holdsite of general 3D curved objects using range data. We develop a three-dimensional generalized Hough transformation which can be also applied to general 3D curved object recognition and which reduces both the computation time and storage requirements. Our approach makes use of the relative geometric differences between particular points on the object surface and some model points which are prespecified arbitrarily and task dependently.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.135-139
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• 1989

The flame initiation of an infinite fuel system exposed to a planar ignition kernel has been investigated numerically. The aim has been to promote an understanding of the flame initiation by using the simplest mathematical formulation which retains the essential physical features. It has been found that there exists a minimum ignition energy below which a combustion wave cannot be initiated. For a fixed value of Lewis number, the same flame progation velocity has been obtained irregardless of the amount ignition energy supplied. Furthermore, for a fixed energy input there is a maximum Lewis number over which the flame cannot be initiated.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.63-71
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• 1997

In this paper, we describe an approach that determines the identity of surfaces of an object with planar and curved surfaces from range data of the object in the scene. The proposed matching scheme presents that surface correspondence of an object is achieved by simple comparison of values for representing surfaces of the object with model in order to avoid unnecessary matching procedures. We use uniquely assigned Surface Representing Value(SRV) for representing surfaces of the object, which are sums of all weighted view-point independent features. And, the proposed method is simple, quite effective and insensitive to occlusion and noise in sensor data.

• ETRI Journal
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• v.38 no.5
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• pp.903-910
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• 2016

We propose a novel multi-stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high-speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS-EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS-EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port-to-port spacing than the unit-cell length, thus overcoming a limitation of previous EBG structures.

• YAKHAK HOEJI
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• v.26 no.1
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• pp.9-23
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• 1982

The structure of 1-butyl-3-sulfanyl urea, ($C_{11}H_{17}N_{3}O_{3}S$) carbutamide has been determined from 575 significant independent reflections collected on an automated four-circle diffractometer. The crystals are orthorhomic, space group, $P2_{1}2_{1}2_{1}$, Z=4, with unit cell dimensions a=9.257 (2), b=9.928 (2), c=15.287 (3)${\AA}$. The structure was solved by the direct methods and refined by least-squares procedure to a final R value of 0.062. Features of the structure include layers of molecules joined by N-H....O hydrogen bond distances ranging from 2.745 to 3.100${\AA}$ involved in a bifurcated hydrogen bond across two fold screw along a and b axes. The atoms forming the urea system are essentially planar.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.10
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• pp.27-36
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• 1992

This paper proposes a numerical method of motion planning for manipulators using Foruier series. For a redundant manipulator, we predetermine the trajectories of redundant joints in terms of the Nth partial sum of the fourier series. then the optimal coefficients of the fourier series are searched by the Powell's method. For a nonredundant or redundant manipulator, CS02T-continuous smooth joint trajectory for a point-to-point task can be obtained while considering the frequency response. We apply the proposed method to the 3-link planar manipulator and the PUMA 560 manipulator. To show the validity of the proposed method, we analyze solutions by the Fast Fourier Transform (FFT). Also, several features are discussed to obtain an optimal solution.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.300.2-300.2
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• 2013

Periodically shaped pillar-arrays and hole-arrays were fabricated on a Si wafer. Geometric features are similar in a periodic length of 4 ${\mu}m$ and a depth of 2 ${\mu}m$. For the hole-array patterns, positive PR processes were performed. UV exposed PR patterns were removed during a developing process to leave shapes of inversely replicated from a glass photomask. Meanwhile, negative PR processes were taken for the pillar-array patterns. UV exposed PR patterns were remained on a Si substrate having a same feature of patterns of a glass photomask. For an electrical aspect, a pillar structure has a short carrier-collection length resulting in the improved open-circuit voltage of 609 mV from 587 mV of a planar device. An improved performance may be achieved to reduce recombination loss along the patterning surface.

• Journal of KIISE:Software and Applications
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• v.32 no.9
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• pp.868-877
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• 2005

Arcs are usually treated as significant features in the field of pattern recognition. This paper presents a method to detect arcs from digital planar curves and estimate their arc centers and radii by using geometric analysis. The deviation of distance between the original curve and the detected arc by the proposed method does not exceed a tolerant error. The experimental results show that the proposed method is available for the detection of arcs iron not only smooth but also heavily noisy curves.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.201-205
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• 1996

The crystal and molecular structure of thiourea dioxide, (NH2)2CSO2, was determined by x-ray single crystal diffraction techniques. Lattice constants are a=10.669(2), b=10.119(2), and c=3.9151(5) Å with the space group Pnma and Z=4. The thiourea portion of the molecule has a planar conformation. When the two oxygen atoms are included, the sulfur atom is at the apex of a trigonal pyramid formed with the two oxygen atoms and the carbon atom as the base. The crystal structure is stabilized by strong intermolecular hydrogen bonds. Ab initio calculations were performed to investigate the bonding features and reactivity of thiourea dioxide. The calculated bond order of S-C is only 0.481. The hydrogen bond energy was computed to be 22.3 kcal/mol for dimer. MEP analysis reveals that the sites on nucleophilic reactions are S and C atoms.