• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.221-224
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• 2004

A theoretical model has been studied to describe the sound radiation analysis for structure vibration noise of vehicle tires under the action of random moving line forces. When a tire is analyzed, it had been modeled as curved beams with distributed springs and dash pots that represent the radial , tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force, damping coefficient and stiffness of foundation will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number, wave-number ratio and stiffness factor. The experimental investigation for structure vibration noise of vehicle tire under the action of random moving line forces has been made. Based on the Spatial Transformation of Sound Field techniques, the sound power and sound radiation are measured. Results strongly suggest that operation condition in the tire material properties and design factors of the tire govern the sound power and sound radiation characteristics.

• 한국정보통신학회논문지
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• 제4권5호
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• pp.971-976
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• 2000

The main objective of this paper is to present the rain cell size distribution observed during squall line episodes in the Sudano-Sahelian region. The used data were collected during the EPSAT Program [Etude des Precipitation par SATellite (Satellites Study of Precipitation)] which has been developed since 1958, on an experimental area located near Niamey, Niger (2 10′32"E, 13 28′38"N). The data were obtained with a C-band radar and a network composed of approximately 100 raingages over a 10,000 $\textrm{km}^2$. In this work a culling of the squall line episodes was made for the 1992 rainy season. After radar data calibration using the raingage network a number of PPI (Plan Position Indicator) images were generated. Each image was then treated in order to obtain a series of radar reflectivity (Z) maps. To describe the cell distribution, a contouring program was used to analyze the areas with rain rate greater than or equal to the contour threshold (R$\geq$$\tau$). 24700 contours were generated, where each iso-pleth belongs to a predefined threshold. Computing each cell surface and relating its area to an equi-circle (a circle having the same area as the cell), a statistical analysis was made. The results show that the number of rain cells having a given size is an inverse exponential function of the equivalent radius. The average and median equivalent radii ate 1.4 and 0.69 In respectively. Implications of these results for the precipitation estimation using threshold methods are discussed.

• 한국CDE학회논문집
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• 제5권2호
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• pp.144-154
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• 2000

We propose an algorithm for obtaining a triangular approximation of a trimmed NLRBS surface. Triangular approximation is used in the pre-processing step of many applications such as RP(Rapid Prototyping), NC(Numerical Control) and FEA(Finite Element Analysis), etc. The algorithm minimizes the number of triangular elements within tolerance and generates a valid triangular mesh for STL file and NC tool path generation. In the algorithm, a subdivision method is used. Since a patch is a basic element of triangular mesh creation, boundary curves of a patch are divided into line segments and the division of curves is applied for the interior of the surface. That is, boundary curves are subdivided into line segments and two end points of each line segment are propagated to the interior of the surface. For the case of a trimmed surface, triangulation is carried out using a model space information. The algorithm is superior because the number of elements can be controlled as the curvature of the surface varies and it generates the triangular mesh in a trimmed region efficiently. To verify the efficiency, the algorithm was implemented and tested for several 3D objects bounded by NURBS surfaces.

• 한국통신학회논문지
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• 제17권1호
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• pp.80-89
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• 1992

화상처리는 전처리, 중간표현, 최종 인식의 3단계로 구분하여 처리할 수 있다. 본 논문에서는 전처리 단계에서 구해진 에지로 둘러싸인 예영역들로부터 라벨링 기법으로 화상을 구분된 영역의 집합으로 표현한 후 각 영역을 둘러 싸고있는 외측 경계과 내측 경계를 세그먼트화하여 각 세그먼트들에 대한 영역의 정보, 세그먼트 번호, 시작점과 끝점의 정보, 적용된 직선 곡선의 종류 및 이들의 개수 정보 리스트에 대한 데이터 구조를 만드는 중간 표현 단계에 대한 알고리즘을 제안하고, 구해진 데이타 구조를 이용 화상을 재구성한 결과 오차가 한 화소 범위내의 신뢰성이 있음을 확인하였다.

• 한국농공학회지
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• 제11권3호
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• pp.1707-1718
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• 1969

The purpose of this experiment is to determine the relations between numbers, arrangements and pumping rates of wells. In this experiment, well pipes were vertically set up in an artificial water-bearing sand layer of homogeneous quality. Wells were arranged in different ways and their number was varied in order to observe the variation of pumping rates. Sands were filled in a square tank, $183cm{\times}91.5cm{\times}91.5cm$ so as to secure a water-bearing layer. Water was constantly supplied from a supply tank located at an end of the tank. The number of well pipes was varied from one to four. Well pipes were connected by a horizontal header pipes were connected by a horizontal header pipe located above them and one pump was used. Pumping rates were measured, when they were arranged in longitudinal and lateral directions, They were also arranged in a square and triangle. The main results thus obtained are presented as follows: (1) When well pipes are laid out in a longitudinal line, i. e., in a flow direction, the ratios of pumping rates of one-pipe well and wells 2-, 3- and 4- pipe t, are 1.903, 2.506 and 2.66, respectively. (2) When well pipes are laid out in a lateral line, i.e., in a perpendicular direction to flow, the same ratios as (1) are 1.912, 2.527 and 2.88. (3) When four pipes are laid out in a square and three pipes are laid out in a triangle, pumping rates are deereased, Comparing with the cases when pipes are laid out in a straight line.

• 천문학회지
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• 제37권4호
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• pp.257-259
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• 2004

We compare the results of the surveys of starless cores performed with CS (2-1) and (3-2) lines to study inward motions in the cores. The velocity shifts of the CS(3-2) and (2-1) lines with respect to $N_2H^+$ are found to correlate well with each other and to have similar number distributions, implying that, in many cores, systematic inward motions of gaseous material may occur over a range of density of at least a factor ${\~}$4. Fits of the CS spectra to a 2-layer radiative transfer model in ten infall candidates suggest that the median effective line-of-sight speed of the inward-moving gas is ${\~}0.07 km\;s^{-l}$ for CS (3-2) and ${\~} 0.04 km\;s^{-l}$ for CS(2-1). Considering that the optical depth obtained from the fits is usually smaller in CS(3-2) than in (2-1) line, this may indicate that CS(3-2) usually traces inner, denser gas with greater inward motions than CS(2-1) implying that many of the infall candidates have faster infall toward the center. However, this conclusion may not be representative of all starless core infall candidates, due to the statistically small number analyzed here. Further line observations will be useful to test this conclusion.

• The International Journal of Costume Culture
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• 제2권2호
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• pp.71-79
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• 1999

The purposes of this study were to 1) identify types and usage levels of production 2) classify apparel manufacturers based on production systems and 3) investigate relationship between characteristics of apparel manufacturers and production system. Apparel manufacturer's characteristics included product line and the number of employees. For this study, the questionnaires were administered to 215 apparel manufacturers in metropolitan area from Feb. to Mar. 1998. Employing a sample of 201, data were analyzed by using factor analysis, descriptive statistics, cluster analysis, discriminant analysis, and multivariate analysis of variance(MANOVA). The following are the results or this study : 1. The production system was identified as three types of production system such as the management centered system, the product centered system and the worker centered system. 2. Based on the three types of the production system, apparel manufacturer were classified into manager centered and product centered groups. 3. With respect to product line, men's wear manufactures were operated the most frequently by manager centered and product centered groups. 3. With respect to product line, men's wear manufacturers were operated the most frequently by management centered system and women's wear manufacturers were operated the most frequently by worker centered system. With respect to the number of employees, apparel manufacturers comprising 5∼19 employees were performed the least frequently worker centered system, while those comprising 50∼99 and 100∼299 employees the least frequently worker centered system.

• 한국정보처리학회논문지
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• 제4권3호
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• pp.802-810
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• 1997

본 논문에서는 n-way Set Associative Cache와 Fully Associative Cache의 유용성 검증을 위하여 direct mapping,2_,4_,16_way set associative mapping 뿐만 아니라 32_, 64_,128_,256_,512_,1024_,2048_,그리고4096_way set assiciative mapping을 사용하는 캐취 의 성능을 제안된 시뮬레이터 프로그램을 실행시켜 분석한다. 일반적으로 캐쉬 메모리 내에있는 하나의 라인보호 내에 수용 가능한 주기억장치의 라인 수 n이 커짐에 따라 그 성능 선형적으로 개선될 것으로 기대되지만, 본 논문의 분석에 따르면 512K 이상의 대용량 캐쉬에서는 n의 변화에 따른 성능 개선이 거의 없는 상태였고 소용량 캐쉬의 경우에도 사용된 라이사이즈가 작은 경우 그 성능개선이 미미하였으며 라인사이즈가 비교적 큰 캐쉬에서는 괄목할 만한 성능개선이 있음을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제19권5호
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• pp.89-98
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• 2014

본 논문은 NP-난제 문제로 알려진 단일모델 단방향 조립라인 균형문제에 대해 휴리스틱 알고리즘을 제안하였다. 조립라인 균형문제는 주로 메타휴리스틱 방법들을 적용하고 있는 추세이다. 제안된 알고리즘은 최종제품이 생산될 때까지 가장 많은 공정으로 조립되는 경로를 주경로로 설정하고, 주경로를 따라가면서 각 작업자에게 순환시간 조건을 만족하는 작업량을 배정하는 군집화 알고리즘을 제안하였다. 제안된 알고리즘은 최소의 작업자수를 결정하고, 순환시간도 단축시키는 결과를 얻었다. 9개의 다양한 실험 데이터에 제안된 주경로 군집화 휴리스틱 알고리즘을 적용한 결과 메타휴리스틱 방법들에 비해 보다 좋은 성능을 갖고 있음을 보였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권8호
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• pp.373-380
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• 2003

This paper consists of a study in post-assembly magnetization of LSPM (Line Start Permanent Magnet Motor). Recently, LSPM is noted as an alternative to the induction motor because it offers a very high efficiency and unity power factor, And it is necessary for permanent magnets to be magnetized by means of post-assembly magnetization in LSPMS because of the manufacturing cost involved. The manufacturing process is also simpler in post-assembly magnetization than in pre-assembly magnetization. Generally, permanent magnet motors are magnetized by their own stator coil or by magnetizing fixtures. However, the permanent magnet in a LSPM is scarcely magnetized by using them because of the eddy current of the rotor bar. Hence, it is necessary to design a magnetizing fixture that overcomes this problem. In this paper, the author analyses the post-assembly magnetization of a LSPM and proposes a method for designing the magnetizing fixture. The method that the author proposes is to make the number of coil turns greater in order to reduce the effect of the eddy current of the rotor bars.