• 천문학회지
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• 제14권1호
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• pp.1-11
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• 1981

Photoelectric drift scans of nearby galaxies, M106, M31 and M33 have been made at diurnal rate with the 61cm Cassegrain Reflector at Sobacksan Observing Station. Luminosity profiles of M106 and M31 show the asymmetries between east and west sides of the galaxies and the near side of each galaxy exhibits a larger B-V color than the far side. B-V color distribution in the central part of MI06 shows somewhat unusual feature of a blue center with red surrounding regions, and this is an opposite trend to the ordinary color distribution of most of external galaxies. B-V color of M31 is nearly constant in the central part of the galaxy while U-B color decreases as the distance from the center increases.

• 천문학회보
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• 제42권2호
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• pp.49.2-49.2
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• 2017

With support from the K-GMT science program (PID: GN-2016B-Q-14), we conducted observations of active asteroid 354P/LINEAR (2010 A2) when it made its closest approach to Earth (i.e., the geocentric distance of 1.06 au on 2017 January 27-28). Taking advantage of the best observing geometry since the discovery, we obtained the first evidence for the rotational status of the largest fragment (~120 m in diameter), which was slowly rotating, that is, the rotational period of 11.36 hours. In addition, we succeed in direct imaging of 10 sub-fragments (~20 m in diameter or larger). Based on these new observational results, we conjecture that this active asteroid was created as a result of catastrophic collision among unknown asteroids. The details of this work are given in Astrophysical Journal Letters, 842, L23.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.137-143
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• 2006

The effect of electric fields on flame speed has been investigated experimentally by observing propagating premixed flames in a tube for methane/air mixtures. The flame speeds were measured in both the normal and micro gravity conditions to substantiate the measurements. The results show that the flame speeds were enhanced by both the AC and DC electric fields, as the flame approached to the high voltage electrode located on the one end of the tube. The enhancement of flame speed was proportional to the square root of the electric field intensity, defined as the voltage applied divided by the distance of flame from the high voltage electrode, when the electric field intensity is sufficiently large. When the electric field intensity was low, there existed critical intensities, below which the electric fields did not influence the flame speed. This critical electric field intensity correlated well with the flame speed.

• 한국표면공학회지
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• 제30권6호
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• pp.400-405
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• 1997

The experimental study has been performed to deposit to deposit chromia powder on magnssium alloy for tribological and mechanical properties. The optimal condition was obtained by changing the spray condition such as working distance and gun power. As ceramics was coated onto the a light metal such as Mg according to the weight reduection of the car engine block, it could acquire that the engine efficiency deu to the weight reduction and properties such as resistance to heat, as well as wear. Coating qualities are discussed with respect to hardness, tribologicalproperty, and microstructure. The tribological and mechanical properties are investigated by using the reciprocal configuration tribometer and microharduess tester. Wear mode is determined by observing the SEM morhpology of wear track and cross section view of wear track.

• 산업경영시스템학회지
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• 제22권50호
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• pp.33-44
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• 1999

This paper describes the Autonomous Vehicles (AV) which are operated for their own tasks. There are chances of conflict resolution such as sharing the same path which can lead to the risk of a collision. This research represents some ways of negotiating the conflict resolution by generating cooperative actions. Negotiation while traveling the path is accomplished by using priority and by announcing the start time of the task. When there is a risk of collision, the AV tries to dissolve the situation of conflict resolution by concurrently adjusting mutual speed and by performing the algorithm of passing. If the speed of the AV cannot be adjusted, it measures the distance between the counterpart of the AV and an obstacle along the path. Then it judges either to proceed by passing the counterpart of the AV or to turn back after observing the current circumstances. The performance of the algorithm described above was proven by a simulator.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.3063-3068
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• 2014

표적의 RCS(Radar Cross Section)는 레이더 탐지 성능을 결정하는데 중요한 요소이므로 표적을 효율적으로 탐지하기 위해 RCS가 크게 나타나는 위치에 레이더를 배치하는 것이 유리하다. 그러나 표적의 RCS와 함께 표적과 레이더 간의 거리 또한 레이더에 수신되는 신호의 강도를 결정하는 중요한 요소이다. 본 논문에서는 탄도미사일을 대상으로 동일한 횡축 선상에서 위치를 변경하면서 표적을 관측하였을 때 레이더에 수신되는 전력을 계산하고, 탐지 효율을 높이기 위한 레이더 배치 방안에 대해 연구하였다.

• 한국통신학회논문지
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• 제40권1호
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• pp.58-60
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• 2015

본 논문은 송신 상관 MIMO 채널에서 SM 시스템의 성능 열화를 극복하는 개루프 프리코딩 기법을 제안한다. 제안 기법은 성상도의 최소거리를 최대화 하는 프리코딩의 피드백 오류에 따른 성능 분석을 통해 제시하였고, 제안한 프리코딩 기법은 수신기로부터 채널 정보의 피드백 없이 성능 열화를 줄일 수 있다.

• 한국조경학회지
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• 제23권3호
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• pp.1-14
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• 1995

The aspect of visual accessibility to urban green spaces is an important factor because it contributes making pleasant environment by increasing the visual experience of nature in urban environment. But we have tried neither to consider nor to measure it. Since he concept of visual accessibility has not formally defined yet, it was operationally defined in this study. And then the model of measuring visual accessibility was suggested and verified through the case study on neighborhood parks in Seoul. The findings are as follows : 1) The concept of visual accessibility is defined as opportunity and potentiality to observe green spaces. 2) The model of measuring visual accessibility deals with not only adjacent area but also viewshed area. In adjacent area, considering factors are the area of road adjacent to green spaces and the area of exposed green spaces. In viewshed area, considering factors are the area of road located in viewshed area, the area of exposed green spaces, and the weight according to observing distance. 3) The final model of measuring visual accessibility suggested in this study is as follows.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.69-80
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• 2014

The free distance of (n, k, l) convolutional codes has some connection with the memory length, which depends on not only l but also on k. To efficiently obtain a large memory length, we have constructed a new class of (2k, k, l) convolutional codes by (2k, k) block codes and (2, 1, l) convolutional codes, and its encoder and generation function are also given in this paper. With the help of some matrix modules, we designed a single structure Viterbi decoder with a parallel capability, obtained a unified and efficient decoding model for (2k, k, l) convolutional codes, and then give a description of the decoding process in detail. By observing the survivor path memory in a matrix viewer, and testing the role of the max module, we implemented a simulation with (2k, k, l) convolutional codes. The results show that many of them are better than conventional (2, 1, l) convolutional codes.

• Macromolecular Research
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• 제10권6호
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• pp.297-303
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• 2002

We have investigated the microstructural properties of a weakly charged polyelectrolyte modeled with both Hookean spring and Debye-Huckel potential, by employing a novel hybrid scheme of molecular dynamics (MD) and Monte Carlo (MC) simulations. Although the off-lattice pivot step facilitates the earlier computations stage, it gives rise to oscillations and hinders the stable equilibrium state. In order to overcome this problem, we adopt the MC off-lattice pivot step in early stage only, and then switch the computation to a pure MD step. The result shows that the computational speed-up compared to the previous method is entirely above 10 to 50, without loss of the accuracy. We examined the conformations of polyelectrolyte in solvents in terms of the end-to-end distance, radius of gyration, and structure factor with variations of the screening effects of solvent and the monomer charges. The emphasis can favorably be given on the elongation behavior of a polyelectrolyte chain, with observing the simultaneous snapshots.