• 대한기계학회논문집
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• 제19권12호
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• pp.3352-3359
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• 1995

An Eulerian-Lagrangian method is employed to simulate the ignition process and the flame propagation through the air/fuel spray mixture in a closed constant-volume combustor. The spray mixture is ignited by providing a hot wall at the end of the combustor or by firing the electric spark. The investigated parameters involve the initial droplet size, overall equivalence ratio, initial fuel vapor concentration, distance between the hot wall and the nearest droplet, and the ignition energy. Numerical results clearly show the existence of the optimum spray condition for minimizing the ignition energy and the ignition delay time as well as the critical dependence of ignition upon the distance of the heat source to the nearest droplet.

• 한국통신학회논문지
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• 제34권5A호
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• pp.331-340
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• 2009

In this paper, we propose a new power loading algorithm for orthogonalized spatial multiplexing(OSM) systems over flat-fading multiple-input multiple-output (MIMO) channels. Compared to SVD-based transmission scheme, the OSM scheme exhibits a good system performance with lower complexity and feedback overhead. To further improve the performance in OSM systems with power loading, we introduce a geometric approach on the Euclidean distance between the constellation points in the effective channel. Using this approach, we show that the optimal power loading parameters in terms of the minimum distance can be obtained. Simulation results demonstrate that our algorithm provides a 5dB gain at a bit error rate (BER) of $10^{-4}$ over that of no power loading case with both QPSK and 16-QAM. Consequently, our power loading algorithm allows us to significantly improve the system performance with one additional feedback value.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.1063-1067
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• 1997

A study of carbide step drill cutting ability is highly progessing the step drill with more then twice diameter rate is so difficult in regrinding and very easy to damage during machining. As the machining of step drill for closed hole is occur to breakage at small diamter poistion, so it is very difficult to machinine. Thue, in this experiment, We investance roundness and surface roghness by machining distance and were identifid that the first distance, 5~10m, was fine with 7 .mu.m but the arround of 15m was happened so much alternation. And we were indentified that after 20m was happend statable machining. The surface roughness was happened the same conditions. So application of stwp drill we think that the selection of cutting conditions need lots consideration and the study of step drill's diameter ratio ratio is carred out.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.59-59
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• 2000

In this paper, we present a framework for modeling and control of multiple mobile robots which cowork within a bounded workspace and limited resources. To achieve this goal, we adopt a formalism of discrete event system and supervisory control theory based on Petri nets. We can divide our whole story into two parts: first, we search the shortest path using the distance vector algorithm, and then we construct the control scheme from which a number of mobile robots can work within a bounded workspace without any collision. The use of Petri net modeling allows us In synthesize a controller which achieves a control specification for the desired closed-loop behavior efficiently. Finally, the usefulness of the proposed Petri net formalism is illustrated by a simulation study.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제20권2호
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• pp.151-161
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• 2016

In this paper, we present a $C^3$ quartic B-spline approximation of circular arcs. The Hausdorff distance between the $C^3$ quartic B-spline curve and the circular arc is obtained in closed form. Using this error analysis, we show that the approximation order of our approximation method is six. For a given circular arc and error tolerance we find the $C^3$ quartic B-spline curve having the minimum number of control points within the tolerance. The algorithm yielding the $C^3$ quartic B-spline approximation of a circular arc is also presented.

• 오토저널
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• 제10권5호
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• pp.42-53
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• 1988

The effects of ignition position on combustion in a chamber with swirl flow were investigated by use of hot wire anemometer, high speed schlieren photography, and chamber pressure measurement. In experiments, the closed-constant volume combustion chamber was used, and the swirl was formed unsteadily by suction of external fluid after reducing pressure in the chamber. Results show that the effect of ignition position on combustion depends on the flow state and the flame propagation distance corresponding to each ignition position. Also, the effect of combustion promoting increases as an ignition position moves from the center of chamber to the outside, but maximum burning pressure was obtained at the position that is the shortest flame propagation distance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.716-721
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• 1990

It is one of the essential task to determine the absolute location of mobile robot during its navigation. In this paper we propose an algorithm to calculate the distance and orientation of camera from landmark through the visual image of stripe typed landmark. Exact closed form solution of camera location is obtained with the correspondences from vertical line on mark plane to the intersection point of projected line with horizontal axis of image plane. It needs only one line image information, so that location determination can be processed in real time.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.6-6
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• 2000

By using the information obtained from the outputs of MR(MagnetoResistive) sensors for an Unmanned Vehicle Driving System, we develop an algorithm that decides the distance and direction between vehicle and the guideline which is made by the magnet. To improve the robust tracking properties of the closed loop system, we introduce H$\infty$ controller and its application for the Unmanned Vehicle Driving System.

• 화약ㆍ발파
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• 제10권1호
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• pp.3-7
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• 1992

In the pilling works in the city, it is tend to transfered to the non-vibration pilling works. This drop-hammer pilling executed with in 2 meters distance to neighbour building structure. in the rainy season. According to imperical formula which tested in similar site, Vibration damaged area is within 14 meters radius from drop-hammer pilling site. The loratories Data of Dae Woo of Korea hausing Authority are refered to above poject.

• 전자공학회논문지S
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• 제35S권7호
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• pp.37-45
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• 1998

In this paper, we extracted heart region using dyamic contour model, increased the vertical resolution of heart region by proposed 2-dimensional interpolation method and visualized the 3-dimensional hearet volutme. the proposed new energy term of dynamic contour model considering the gray level and direction of controur vectors is effective to extract the closed heart boundary. And, we generatedvertical slice images from the extracted heart region images using the 2-dimensional linear interpolation by DT(distance transform). We showed that proposed algorithm is useful by 3-dimensional visualization of heart volume.