• Journal of the Institute of Convergence Signal Processing
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• v.7 no.1
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• pp.38-44
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• 2006

The omnidirectional mobility of a mobile robot may lose significance in motion control, unless the isotropy characteristics of the mechanism is maintained well. This paper investigates the local and global isotropy of an omnidirectional mobile robot with three caster wheels. All possible actuations with different number and combination of rotating and steering joints are considered. First, the kinematic model based on velocity decomposition and the algebraic conditions for the local isotropy are obtained. Second, the geometric conditions for the local isotropy are derived and all isotropic configurations are fully identified. Third, the global isotropy index is examined to determine the optimal parameters in terms of actuation set, characteristic length, and steering link length.

• Journal of the Korean Ceramic Society
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• v.36 no.7
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• pp.711-717
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• 1999

Biaxial fracture behavior of alumina specimens with the diameter of 20mm and four kinds of thickness of 1.9, 2.3, 2.6 and 2.8mm was studied by the ball-on-3-ball test and the fracture results were analyzed by he analysis of variance (ANOCA), The strength measured with the down speed prescribed in ASTM showed that the measured strength was not dependent on the thickness of the specimens. Equivalent radius and crack-braching number were observed to increase lineraly with the thickness of the specimens. The jog direction was observed to study the effect of grinding direction on surface flaws. It is though that the surface finishing with #600 grit diamond wheel did not affect the surface flaws of the specimens.

• Journal of the Korea Safety Management & Science
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• v.5 no.1
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• pp.69-82
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• 2003

The sequence which minimizes overall utility work in car assembly lines reduces the cycle time, the number of utility workers, and the risk of conveyor stopping. This study suggests mathematical formulation of the sequencing problem to minimize overall utility work, and present a genetic algorithm which can provide a near optimal solution in real time. To apply a genetic algorithm to the sequencing problem in car assembly lines, the representation, selection methods, and genetic parameters are studied. Experiments are carried out to compare selection methods such as roullette wheel selection, tournament selection and ranking selection. Experimental results show that ranking selection method outperforms the others in solution quality, whereas tournament selection provides the best performance in computation time.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.283-289
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• 2004

Rail defects(Corrugation, shelling, etc) are occurred by the Rail with wheel contact stress. Rail grinding is maintaining of optimal rail profile to use special rail grinding machine to remove rail defect. The benefits of rail grinding enforcement, improve track safety, improve track steering and rail life, improve ride comfort and reduce noise, etc. Actually when rail grinding plan apply to field track, we should consider a lot of function before determination, such as grinding method, grinding pass number, removing metal volume, etc. because each track has various characteristics. Therefore it is important that the determination of rail grinding strategy for optimum and economic before enforcement.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.463-470
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• 2000

The challenge to be faced in public transportation today is to satisfy human needs with the least delay, with the smallest number of accidents, and with the most economic use of energy, space, materials, man-power and money. One possible solution may lie in city train system, including AGT system. Specially, Passenger space in AGT is important to balance the budget of layout with passenger's satisfaction. This study focuses on lay-out and space, comfort which should be considered from the conceptual design stage of the interior layout work. Traditionally, the interior layout of the passenger room has emphasized ridequality and style. However, as the train becomes more prevalent and versatile, the focus also tends to shift toward layout and space to have comfortable circumstances. After all, the purpose of this research focused on arrangement a rational interior layout of the train through ergonomics research. Finally, the key was ensuring the comfortable environment based on cultural background of the passenger.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.353-361
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• 2002

An experimental study was made of turbulent separated and reattaching flow over a blunt body, where unsteady wake was generated by a spoke wheel-type wake generator with cylindrical rods. The influence of unsteady wake was scrutinized by altering the rotating direction (CW and CCW) and the normalized passing frequency (0 St$\_$H/ 0.20). The Reynolds number based on the cylindrical rod was Re$\_$d/=375. A phase-averaging technique was employed to characterize the unsteady wake. The effect of different rotating directions was examined in detail, which gave a significant reduction of x$\_$R/. The wall pressure fluctuations on the blunt body were analysed in terms of the spectrum and the coherence.

• Journal of applied mathematics & informatics
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• v.39 no.3_4
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• pp.497-506
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• 2021

Let G be a graph. Let f : V (G) → {0, 1, …, k - 1} be a function where k ∈ ℕ and k > 1. For each edge uv, assign the label $f(uv)={\lceil}{\frac{f(u)+f(v)}{2}}{\rceil}$. f is called k-total mean cordial labeling of G if ${\mid}t_{mf}(i)-t_{mf}(j){\mid}{\leq}1$, for all i, j ∈ {0, 1, …, k - 1}, where t_mf (x) denotes the total number of vertices and edges labelled with x, x ∈ {0, 1, …, k-1}. A graph with admit a k-total mean cordial labeling is called k-total mean cordial graph.

• Journal of the Chungcheong Mathematical Society
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• v.35 no.3
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• pp.205-225
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• 2022

In this paper, we derive analytical closed results for the first (a, b)-KA index, the Sombor index, the modified Sombor index, the first reduced (a, b)-KA index, the reduced Sombor index, the reduced modified Sombor index, the second reduced (a, b)-KA index and the mean Sombor index mSO_α for the OTIS biswapped networks by considering basis graphs as path, wheel graph, complete bipartite graph and r-regular graphs. Network theory plays a significant role in electronic and electrical engineering, such as signal processing, networking, communication theory, and so on. A topological index (TI) is a real number associated with graph networks that correlates chemical networks with a variety of physical and chemical properties as well as chemical reactivity. The Optical Transpose Interconnection System (OTIS) network has recently received increased interest due to its potential uses in parallel and distributed systems.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.164-170
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• 1993

Panax ginseng has been reported to protect animals or to help them recover from physical, chemical, or biological stress. The antistress effects of ginseng were evaluated through the measurement of adrenal ascorbic acid, rectal temperature, and plasma level of glucose. lipids and corticosterone. During the treadmill experiments of the antifatigue study, the groups of rats receiving P. ginseng or P. quinquefolius extracts were consistently found to leave fewer fecal boli on the wheel compared with controls. This phenomenon may be due to the reported antistress effects of ginseng. Another possibility could be that the Panax species examined produced anticholinergic effects which in turn inhibited the production of fecal boli. After an anticholinergic study. employing physostigmine and atropine as controls, anticholinergic effect was found not essential for the decrease of fecal boli number left on the wheels during antifatigue studies. The results were consistent with the antistress activity reported previously. Even though the active constituents responsible for the antistress effects of ginseng remained to be determined, the fecal boli counts for stressed rats can be employed as a new protocol for evaluating the antistress effects of ginseng.

• Korean Journal of Cognitive Science
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• v.26 no.1
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• pp.27-51
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• 2015

The present study tested the effect of a top-down influence on recalling the colors of Stroop words. Participants remembered the colors of 1, 2, 3 or 6 Stroop words. After 1 second of a memory delay, they were asked to recall the color of a cued Stroop word by selecting out its corresponding color on a color-wheel stimulus. The correct recall was defined when the participants chose a color that was within ${\pm}45^{\circ}$ from the exact location of Stroop word's color on the color-wheel. Otherwise, the recall was defined as incorrect. The analyses of the frequency distribution of the participants' responses in the error trials showed that the probability of choosing the color-name of the target Stroop word was higher than the probability of other five color-names on the color-wheel. Further analyses showed that increasing the number of Stroop words to manipulate memory load did not affect the probability of the Stroop interference. These results indicate that the top-down interference by Stroop manipulation may induce systematic distortion of the stored representation in visual working memory.