• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.47-53
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• 2007

The laminar combustion characteristics of interacting coal particles in a convective flow are numerically investigated at particle arrangement and size difference. The numerical simulations, which use the two-step global reaction model to account for the surrounding gas effect, show the detailed interaction among the inter-space particles, undergoing devolatilization and subsequent char burning. Several parametric studies, which include the effect of the gas temperature (1700 K), high pressure(10 atm) and variation in geometrical arrangement of the particle diameter on the volatile release rate and the char combustion rate, have been carried out. The comparison indicates that the shift to the multiple particle arrangement resulted in the substantial change of the combustion characteristics and that the volatile release rate of the interacting coal particles exhibits a strong dependency on the particle spacing and size difference.

• Annual Conference on Human and Language Technology
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• 1994.11a
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• pp.223-230
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• 1994

본 한글꼴은 음절 및 음소의 가시성을 높이고자 한글 음소의 이중 가로선형 배열을 통한 밀도 분산형 한글꼴과 음소 나열형 한글꼴 등의 새로운 한글꼴의 다양한 표현의 실험 연구이다. 일도 분산형 한글꼴은 새로운 음소형 한글코드(닿소리, 홑소리, 받침 조합형)와 서로 대응하드록 일원화 한글꼴로 한글 및 옛 한글의 음소 조합형의 입.출력이 가능하다. 이러한 시도는 1바이트 이내에서 현대한글 및 옛한글을 구현하며, 이는 한글의 구현원리에 따른 음소형 코드체계의 실현 가능성으로 한글 코드체계의 최적화에 대한 새로운 가설을 제시 한다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.205-208
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• 2001

기존 의료용 초음파 진단장치에 사용되고 있는 선형 배열 탐촉자를 대상으로, 과도음장의 전파특성을 해석하고, 음장 변화에 민감하게 영향을 미치는 구동 펄스의 형태 및 탐촉자의 요소의 크기(element width), 곡률반경(Radius of curvature), 초점길이(focal length) 등 구조적인 변화에 따른 과도음장 전파 특성의 변화 양상을 시뮬레이션을 통해 체계적으로 해석하였다. 나아가, 매질이 간, 근육, 지방 등의 생체 조직인 경우의 음장 변화 특성을 비교 분석하였다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.8
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• pp.1985-1996
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• 1998

A parallelising algorithm for partitioning and mapping methods of matrix/vector multiplication into linear processor array/VLW simulator is presented in this paper. First we discuss the mapping methods for input matrix or vector into the arbitrarily size of processor arrays. Then, we show partitioning the algorithmss of the large size of computational problem into the size of the processor array. We execute the algorithm on VLIW simuhator and show to effectiviness of algorithm. The result which we achived better parallelising performance on our VLIW simulator dsign than on linear processor array.

• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.181-185
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• 1993

물 속에 만들어진 공기방울들은 각자 자신의 반지름에 반비례하는 공진주파수로 음파를 방출하며, 많은 공기방울들이 모인 공기방울 집단은 집단의 전체 크기에 반비례하는 집단 공진주파수를 가진다는 현상이 그동안 연구되어 왔다. 그러나, 수십, 수백 개의 유한한 개수를 가진 공기방울들의 음파방출 주파수 특성 연구는 부족한 실정이다. 본 연구에서는 수중에 일차원 배열의 공기방울들을 발생시켜 공기방울들에서 나오는 음파방출 주파수를 측정하였다. 수중에 형성된 공기방울들은 그들 간에 거리 간격이 존재하므로 본 연구에서는 공기방울들 간의 상호작용이 변화한다고 간주한 유효 결합 조화진동자 모형을 새로이 만들어 해석하였으며, 실험값과 좋은 이치를 보여주었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.174-181
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• 2014

Design procedure of LEG(Linear Electric Generator) is introduced by performing the time-domain analysis for the heaving motion of a floating buoy coupled with LEG. A vertical truncated buoy is selected as a point absorber and a double-sided Halbach array mover and cored slotless stator is adopted as a linear electric generator. LEG with a double-sided Halbach array mover and cored slotless stator is designed with the input data such as the heave motion velocity and wave exciting forces in time-domain. The validity of designed LEG is confirmed by performing generating-characteristic-analysis under the sinusoidal motion of a buoy, based on the numerical techniques such as FE(Finite Element) analysis. In particular, an ECM(Equivalent Circuit Method) is employed as the design tool for the prediction of generating characteristics under irregular wave conditions. Finally, we confirm that the ECM gives reasonable and fast results without sacrifice of accuracy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.250-259
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• 2012

This paper compared and investigated the choice of optimal algorithm affects on the directivity synthesis of linear array in the satisfaction to the design specification of the desired directivity, convergence characteristic, and adaptability. Optimal algorithms use a quasi-Newton method(DFP and BFGS method) for realizing the desired directivity, used a quasi-ideal beam, steering beam, and a multi-beam, chosen as desired directivity. In the numerical result, this paper verified the effectiveness of the quasi-Newton method to the directivity synthesis, and offered a solving approach of occurred problems in the numerical simulation process.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1279-1290
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• 2007

In this paper, a cylindrical hybrid antenna which is spatially fed by an off-set linear feed array is described to form complex beam patterns. The linear feed array consists of twelve micro-strip patch elements and forms a flat-topped beam pattern with a beam-width of $90^{\circ}$ in the horizontal plane. The vertical curve on the cylindrical reflector with the linear feed array is shaped in order to form a cosecant beam pattern within the range of $-5^{\circ}$ to $-25^{\circ}$ in the vertical plane. To form complex beam patterns, the hybrid antenna with cylindrical reflector aperture of $140{\times}50\;cm$ was designed and fabricated to be operated within the IMT 2000 service band, and also electrical performances of the antenna were measured and analyzed.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.58-65
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• 2015

This paper deals with the generating characteristic analysis of permanent magnet linear generator (PMLG) with double-sided Halbach magnet array mover and three phases concentrated stator windings by using analytical method. On the basis of a magnetic vector potential and Maxwell's equations, governing equations are obtained, and magnetization modeling for Halbach magnet array is performed analytically by using the Fourier series. And then, we obtain electrical parameters such as back-EMF constant, resistance, and coil inductance based on magnetic field calculations. Finally, analytical results for generating performance are confirmed by comparing with finite element analysis results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.163-173
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• 2012

This study covers the nonlinear analysis of anchor head for high strength prestressing strand and presents necessary process in improving the performance of anchor head. The surface of wedge for strand is contacted to the surface of the wedge hole on anchor head when it is fitted into the wedge hole, and the contact condition changes according to the level of load applied through the wedge. In order to analyze detailed behavior, nonlinear material model and contact element were used in analysis. It was found from the analysis that the behavior of anchor head is affected by the interaction with the wedge contacted so that the wedge in FE model should have the same figure as the actual object. Circular array of wedge hole presents better stress distribution than layer array even though the small difference in maximum deformation. Increment of thickness of anchor head and distance of wedge hole also improve the performance of anchor head.