• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.538-539
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• 2008

유비쿼터스 컴퓨팅의 실현을 위해 센서 네트워크 기반의 다양한 위치인식 연구가 수행되었다. 특히 근거리 위치 인식 분야에서는 RSSI를 이용한 위치 인식에 관한 연구가 활발하였으나 RSSI는 통신 환경에 민감하여 균일한 위치 정보 결과를 획득하기 어려우며, RSSI 값을 기반으로 삼각측량 등의 위치 계산을 소프트웨어적으로 처리하기 때문에 응답 속도가 늦다는 단점이 있다. 따라서 최근 Chipcon에서는 CC243x 시리즈에 위치 계산 엔진(Location Engine)을 탑재하여 응답 속도에 대한 종전의 단점을 보완하였으나 여전히 위치 값이 고르지 못한 부분은 개선되지 않았다. 따라서 본 논문에서는 통신 환경으로 인한 위치 정보의 불균등함을 개선하고자 선형 윈도우 알고리즘을 제안한다. 선형 윈도우는 위치 정보에 대한 스무팅을 수행하며, 이를 통해 응답 속도의 저하를 최소화시키면서 위치 변화를 고르게 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.305-307
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• 2016

The purpose of this paper is to determine the optimal values of the gain parameters used in the tracking module for a highly dynamic warship. The algorithm of the tracking module uses the ${\alpha}-{\beta}-{\gamma}$ filter to compute accurate estimates and update the state variables, that is, positions, velocity and acceleration. The filtering coefficients ${\alpha}$, ${\beta}$ and ${\gamma}$ are determined from set values of the damping parameter, ${\xi}$. Optimization is achieved by plotting a range of the damping parameter ${\xi}$ against the corresponding residual error and then selecting the best value of ${\xi}$ with the minimum residual error. Optimal values of the smoothing coefficients are subsequently computed from the selected damping parameter, ${\xi}$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.699-704
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• 2002

A method using beamforming algorithm has been developed to measure oblique incidence reflection coefficients of sound absorption materials. MUSIC(Multiple Signal Classification) method detects the angles of incidence and reflection. By separating the incident and reflected waves using beamforming method, the reflection coefficient is calculated. Spatial smoothing technique is also used to reduce the coherence between the incident and reflected waves. The test materials were modeled as a locally reacting surface. Numerical and experiment results are performed to verify the acuracy of proposed method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.237-238
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• 2013

The quality of document image captured from electronic display might be worse when it is compared with document image captured from paper. The problem appears because of Moir? noise. This problem can lead to achieve inaccurate intermediate result for further image processing. This paper proposes a method to remove Moir? noise of document images captured from electronic display. The proposed algorithm is separated in two parts. In the first step, it corrects the text area region (foreground) with small area of smoothing. Then, it corrects the background area with large area of smoothing.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.5
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• pp.193-198
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• 1986

In this paper, 1-168 hours ahead load prediction algorithm is developed for power system economic weekly operation. Total load is composed of three components, which are base load, week load and weather-sensitive load. Base load and week load are predicted by moving average and exponential smoothing method, respectively. The days of moving average and smoothing constant are optimally determined. Weather-sensitive load is modeled by linear form. The paramiters of weather load model are estimated by exponentially weighted recursive least square method. The load prediction of special day is very tedious, difficult and remains many problems which should be improved. Test results are given for the day of different types using the actual load data of KEPCO.

• Korean Journal of Computational Design and Engineering
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• v.11 no.2
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• pp.107-114
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• 2006

A new quadrilateral mesh generation technique from an existing triangle mesh is proposed in this paper. The proposed method is based on advancing front method and zero-thickness layer. Beginning with an initial triangular mesh, boundary triangular elements are removed and quadrilateral elements with zero thickness are generated. A quality of quadrilateral elements is improved during a mesh smoothing process. Until all initial triangular elements are removed, this procedure is repeated. Sample meshes are constructed to demonstrate the mesh generation capability of proposed algorithm.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.835-836
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• 2008

This paper presents a new method of segmenting characters in a car licence plate which is less influenced by illumination variation. It uses an anisotropic filter to reduce the lighting noise and a histogram specification scheme to obtain the binary image. Anisotropic smoothing filter process the input images, which are acquired under different lighting conditions, so that they may have similar image quality. The enhanced performance of the proposed algorithm has been proved by the experiment.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.24-29
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• 1999

In this paper, a simple contour-preserving filtering algorithm is proposed. The goal of the contour-preserving filtering method is to remove noise ad granularity as the preprocessing for the image segmentation procedure. Our method finds edge map and separates the image into the edge region and the non-edge region using this edge map. For the non-edge region, typical smoothing filters could be used to remove the noise and the small areas during the segmentation procedure. The result of simulation shows that our method is slightly better than the typical methods such as the median filtering and gradient inverse weighted filtering in the point of view of analysis of variance (ANOVA).

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.460-470
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• 2004

A computational analysis of engineering problems with moving domain or/and boundary according to either Lagrangian or Eulerian approach may encounter inherent numerical difficulties, the extreme mesh distortion in the former and the material boundary indistinctness in the latter. In order to overcome such defects in classical numerical approaches, the ALE(arbitrary Lagrangian Eulerian) method is widely being adopted in which the finite element mesh moves with arbitrary velocity. This paper is concerned with the ALE finite element formulation, aiming at the dynamic response analysis of baffled fuel-storage container in yawing motion, for which the coupled time integration scheme, the remeshing and smoothing algorithm and the mesh velocity determination are addressed. Numerical simulation illustrating theoretical works is also presented.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.3-6
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• 1988

The UCERSS algorithm is an extended MUSIC which is used to estimate incident angles of multiple wide band signals. The purpose of this paper is to extend the UCERSS in order to estimate the direction of arrivals of multiple wide band signals in multipath environment. The modifications of the UCERSS result in the wide band spatial smoothing and the UNSS approaches. Computer simulation results indicate that the performances of the UNSS are superior to those of the UCERSS and the wide band spatial smoothing method.