• 한국음향학회지
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• 제31권1호
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• pp.51-61
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• 2012

본 연구에서는 등각, 등간격 및 측지선 돔 (geodesic dome)형태로 배열된 곡면 배열 트랜스듀서에 대해서, 음원 간격, 음원 개수 등과 같은 배열 구조 변수들에 따른 방사패턴의 변화 경향성을 분석하였다. 또한 그 결과를 바탕으로 통계적 기법인 다중 회귀 분석을 이용하여 부엽의 크기 및 빔 폭을 설계 변수들의 함수로 도출하였다. 나아가 최적화 기법인 GA (genetic algorithm)법을 이용하여 각 방향에 대한 빔폭이 주어진 조건을 만족하며 가장 작은 부엽의 크기를 가지도록 설계 변수들의 최적화를 수행하였다. 최적화 결과를 바탕으로 세 가지 곡면 배열 구조 가운데 곡면 배열 트랜스듀서의 최적 배열 구조로 등간격 배열구조를 선정하였다.

• 한국음향학회지
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• 제29권7호
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• pp.431-438
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• 2010

곡면에 지지된 음원의 경우 음원의 배열 방식에 따라 방사되는 음장이 매우 복잡한 특성을 가진다. 본 연구에서는 곡면 배열 트랜스듀서를 구성하는 음원을 등각, 등간격 그리고 geodesic dome 형태로 배열하여, 각각의 배열 방식에 따른 음향 방사 패턴 함수를 유도하고, 그에 따라 방사 패턴을 해석하였다. 해석 결과를 바탕으로 3가지 배열 방법 가운데 상대적으로 주엽의 빔 폭이 크고 부엽의 크기가 작은 경향을 보이는 등간격 배열을 곡면 배열 트랜스듀서의 구조로 선정하였다. 본 연구 결과는 곡면 배열 트랜스듀서의 구조 설계에 활용될 수 있을 것으로 기대된다.

• 대한의용생체공학회:의공학회지
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• 제17권4호
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• pp.469-478
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• 1996

In the conventional digital ultrasound scanner, the reflected signal is sampled either in polar coordinates of R-$\theta$ method, or in Cartesian coordinates of uniform ladder algorithm (ULA). The R-$\theta$ scan method necessitates a coordinate transform process which makes hardware complex in comparison with ULA scan mrthoA In spite of this complexity, R-$\theta$ method has a good resolution in ultrasonographic (US) image, since scan direction of the US imaging is a radial direction. In this paper, a new digital scan converter is proposed, which is named the radius uniform ladder algorithm (RULA). The RULA has the rome scan direction as the US scanning in the radial direction and as the display space in the $\theta$ direction. In tllis new approach, sampled points we uniformly distributed in each horizontal line i.n well as in each radial ray so that the data are displayed in the Cartesian coordinates by the 1-D interpolation process. The propped algorithm has an uniform resolution in the periphery and the center field in comparison with equi-angle ULA and equi-interval ULA. To extend the scan angle, concentric square raster sampling (CSRS) is adopted with reduction of discontinuities on the junctions between horizontal scan and vertical scan. The discontinuities are reduced by using the hmction filtering along the $\theta$ direction.

• 대한인간공학회지
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• 제24권4호
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• pp.31-37
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• 2005

Resulting anthropometric data recently measured and cataloged through 5th national anthropometric survey that is called Size Korea is highly useful in clothing industries. This study aims at suggesting a statistical methodology for apparel sizing that reflects recent changes in Korean anthropometry and improves customer fitness. Based on previous research on body types such as triangular, rectangular, inverted body types, etc., factors that represent human sizes were extracted and then clustered into groups by their body types. These body type-based groups with respect to the factors obtained yielded a sizing system of which the interval of each factor is of equi-distance by their factor scores. However, each interval of the sizing system is non-linear in terms of individual anthropometric variables. The sizing system being proposed in this study was compared to that of KS K 0050 and had a broader coverage for the Korean population surveyed. The apparel sizing scheme is expected to improve customer fitness when applied to garment sizing and to provide more information on what percentage of population is included in each classification.

• Journal of the korean society of oceanography
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• 제36권3호
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• pp.83-92
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• 2001

An investigation on the zonal communities in Chokchon macrotidal flat, Incheon, Korea, was carried out on July 1994, eight years after the initial survey done by Frey et al. (1987a and b). A survey transect (4 km long) was established with 41 stations having an equi-interval of 100 m. Macrofaunas were sampled in July 1994. R-mode cluster analysis and ordination analysis (detrended correspondence analysis or DCA) were performed. The aims of the investigation were to: (1) observe the distribution and abundance patterns, including zonation of benthic macrofaunal communities in the area; and (2) gain information about faunal changes between two different periods. The primary feature of distribution was corresponded with Frey's zonation, and this was shaped by three level-specific species groups. Significant changes in dominant species were detected when compared with the faunal assemblages of 1986. The bivalve mollusk, Meretrix petechialis, seemed to have disappeared. Two newly arrived organic pollution indicator species, Theora fragilis and Capitella capitata, were regarded as impregnable proof of response to eutrophication, although the concrete evidence on the eutrophication source was not found.

• 한국정밀공학회지
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• 제19권8호
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• pp.172-179
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• 2002

In this paper, an efficient reverse engineering method for free-formed surfaces is proposed based on the integration of a repetitive digitizing method and vision system. In recent reverse engineering process, the equi-interval digitization method is being used since the surface information is not known. If more accurate results are required, the number of measuring point should be increased appropriately. Thus, such measuring process tends to result in too dense data including useless information, and cause excessive measuring time. This problem can be improved by applying repetitive digitizing method and image process technique, which is proposed in this paper. The proposed methods are validated through appropriate simulation and experiments.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2000년도 추계 학술 발표회 논문집
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• pp.5-10
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• 2000

In case of outputting the image with color printer, image is occurred color distortion by characteristics of paper, effect by overlap between neighbor dots and the mechanical characteristics if printer. Color calibration is needed to reduce this color distrotion. To color calibration, we select the color sample in printer color gamut. The accuracy of color calibration is determined by the number of sample, distribution, and calibration method. Generally, color space is selected the color sample dividing equal interval. In this case, the range of gamut of printed color patches is reduced due to the effect of inks overlap. Therefore, error is occurred when color transformation relatively. In this paper, we have the color sampling based on equi-visual perception and then reproduce the color using the Neural-Network and interpolation by LUT.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3030-3032
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• 1999

This Paper proposes a fuzzy algorithm for cooperative behaviors of multiple autonomous mobile robots. Each robot makes decision of his behavior based on the information obtained by infrared sensors to measure the position and velocities of other robots. The effectiveness of the proposed algorithm is shown by some computer simulation where a group of mobile robots encircles with equi-interval.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.3165-3181
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• 2019

Spherical videos, which are also called 360-degree videos, have become increasingly popular due to the rapid development of virtual reality technology. However, the large amount of data in such videos is a huge challenge for existing transmission system. To use the existing encode framework, it should be converted into a 2D image plane by using a specific projection format, e.g. the equi-rectangular projection (ERP) format. The existing high-efficiency video coding standard (HEVC) can effectively compress video content, but its enormous computational complexity makes the time spent on compressing high-frame-rate and high-resolution 360-degree videos disproportionate to the benefits of compression. Focusing on the ERP format characteristics of 360-degree videos, this work develops a fast decision algorithm for predicting the coding unit depth interval and adaptive mode decision for intra prediction mode. The algorithm makes full use of the video characteristics of the ERP format by dealing with pole and equatorial areas separately. It sets different reference blocks and determination conditions according to the degree of stretching, which can reduce the coding time while ensuring the quality. Compared with the original reference software HM-16.16, the proposed algorithm can reduce time consumption by 39.3% in the all-intra configuration, and the BD-rate increases by only 0.84%.

• 한국컴퓨터그래픽스학회논문지
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• 제25권3호
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• pp.143-152
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• 2019

본 논문은 3차원 물방울 조형 생성장치로 구현된 3차원 물방울 조형을 생성할 때 위성 물방울이 생성되지 않고 형상 왜곡이 일어나지 않으면서 조형의 해상도를 최대한으로 높일 수 있는 기법을 제안한다. 3차원 물방울 생성장치는 보통 표현하고자 3차원 조형을 등 간격으로 배치된 슬라이스들의 집합으로 이산화하여 표현하고 각 슬라이스를 순서대로 읽어 각 슬라이스를 실현하는 물방울을 솔레노이드 밸브를 개폐하여 생성한다. 각 슬라이스의 해상도는 솔레노이드 노즐 매트릭스의 해상도와 같다. 본 논문에서는 위성 물방울이 생성되지 않으면서 형상의 왜곡도 생기지 않는 새로운 기법 두 가지를 제시하고자 한다. 첫째 방법은 등간격 기법이라고 하는데, 등간격으로 배치된 각 슬라이스를 생성하는 시점을 조절하여 중력에 의해 시간이 지날수록 물방울의 속도가 빨라지더라도 조형 전체가 다 형성되는 순간에 물방울 슬라이스들이 등 간격을 유지하게 하여 원래의 형상이 왜곡되는 것을 방지한다. 두 번째 방법은 최소시간 간격 기법이라고 하는데, 3차원 조형을 슬라이스로 이산화시킬 때, 슬라이스를 등 간격으로 배치하는 것이 아니라 가능한 한 촘촘하게 배치한다. 중력을 고려하여 조형 위쪽으로 갈수록 슬라이스를 더 촘촘하게 배치하고, 아래로 내려올수록 슬라이스 간의 간격이 늘어나게 배치한다. 이때 주어진 노즐의 성능 한도 내에서 최대한 촘촘하게 불균등 간격 슬라이스를 배치하고 조형이 완성되는 시점에 이 간격이 실현되게끔 노즐 개폐를 제어한다. 이 방법을 구현하기 위해 주어진 물방울 생성장치의 솔레노이드 밸브가 위성 물방울 생성 없이 인접한 두 물방울을 연달아 생성하는데 필요한 최소 시간 간격 (노즐 오픈 명령후 노즐이 완전히 오픈되는데 걸리는 시간과 완전 오픈상태를 유지하는 시간, 그리고 노즐 클로즈 명령후, 노즐이 완전히 클로즈 되는데 걸리는 시간의 합) 을 실험으로 구했다. 두 번째 방법은 첫 번째 방법에 비해 조형의 해상도가 상당히 증가하는 장점이 있다.