• International Journal of Precision Engineering and Manufacturing
• /
• 제6권2호
• /
• pp.12-18
• /
• 2005

A geometric compensation of thin-walled molded parts in reverse engineering is presented. Researches in reverse engineering have focused on the fitting of points to curves and surfaces. However, the reconstructed model is not the geometric model because the molded parts have some dimensional errors in measurements and deformation during molding. Geometric information can give an improved accuracy in reverse engineering. Thus, measurement data must be compensated with geometric information to reconstruct the mathematical model. The functional and geometric concepts of the part can be derived from geometric information. LSM (Least square method) is adopted to determine the geometric information. Also, an example of geometric compensation is given to improve the accuracy of geometric model and to inspect the reconstructed model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.226-228
• /
• 2001

this paper presents the distance relay using wavelet transform and least square error method. Wavelet transform detect the faults in the high frequency region and remove the noises in the low frequency region. The variable window length LSE determine optimal window length to each fault case and estimate fault impedance very quickly.

• 전기학회논문지P
• /
• 제56권4호
• /
• pp.179-185
• /
• 2007

In this paper, the method of computing demand rate with respect to a transformer capacity is proposed and addressed to predict a future demand rate. The simulation data are taken from switchgears of a real medium voltage transformer. Data taken from the electrical instrument at 22.9 kVY power receiving panels are employed to evaluate the correlation between demand rate and power usage of transformer. It is verified a usefulness with respect to an proposed index of demand rate for transformer by using a least square error of regressive modeling, As a result of investigation and simulation on the spot to a few buildings, it is considered that there is necessity to make a partial amendment of demand rate being applicable currently for electrical energy saving in domestic.

• 약학회지
• /
• 제48권1호
• /
• pp.60-64
• /
• 2004

Near-infrared (NIR) spectroscopy was used to determine rapidly and nondestructively the content of ambroxol in intact ambroxol tablets containing 30 mg (12.5％ m/m nominal concentration) by collecting NIR spectra in range 1100-1750 nm. The laboratory-made samples had 10.3∼15.9％ m/m nominal ambroxol concentration. The measurements were made by reflection using a fiber-optic probe and calibration was carried out by partial least square regression (PLSR) with autoscaling. Model validation was performed by randomly splitting the data set into calibration and validation data set (7 samples as a calibration data set and 5 samples as a validation data set). The developed NIR method gave results comparable to the known values of tablets in a laboratorial manufacturing Process, standard error of calibration (SEC) and standard error of prediction (SEP) being 0.49％ and 0.49％ m/m respectively. The method showed good accuracy and repeatability NIR spectroscopic determination in intact tablets allowed the potential use of real time monitoring for a running production process.

• 대한안전경영과학회지
• /
• 제14권1호
• /
• pp.209-215
• /
• 2012

This paper deals with the construction of system for correct location determination of fixed tag. We adapted to construct the above method. Also we adapted the several filtering method. This system was constructed through using of several filtering methods to decrease the location determination error and fingerprint method which is composed of training phase and positioning phase. We constructed this system using Labview 2010 and MS-SQL 2000 as database. This system results in less location determination error than least square method, triangulation positioning method, and other fingerprint methods.

• 한국정밀공학회지
• /
• 제15권7호
• /
• pp.167-174
• /
• 1998

This paper presents an unoccluded cylindrical object pose measurement using a slit beam laser in which a robot recognizes all of the unoccluded objects from the top of jumbled objects, and picks them up one by one. The elliptical equation parameters of a projected curve edge on a slice are calculated using LSM. The coefficients of standard elliptical equation are compared with these parameters to estimate the object pose. The hamming distances between the estimated coordinates and the calculated ones are extracted as measures to evaluate a local constraint and a smoothing surface curvature. The edges between slices are linked using error function based on the edge types and the hamming distances. The linked edges on slices are compared with the model object's length to recognize the unoccluded object. This proposed method may provide a solution to the automation of part handling in manufacturing environments such as punch press operation or part assembly.

• 융합신호처리학회논문지
• /
• 제12권3호
• /
• pp.163-168
• /
• 2011

본 논문은 감마보정을 위한 비선형 곡선 알고리즘의 개선에 관한 연구이다. 기존의 비선형 감마 곡선 생성 방법은 Gauss-Jordan 역행렬을 적용한 최소 자승 다항식(Least Square Polynomial)을 사용하였다. 이 방법은 다항식 계수 값 계산 과정 중 고차행렬의 역행렬 연산에서 $10^{-11}$ 이하의 매우 작은 값은 절단함으로써 곡선접합의 정밀도가 감소된다. 또한 입력으로 사용되는 샘플 포인트가 10-bit 기준으로 0~1023의 밝기 값에 대하여 고루 분포되어있는 경우에만 정확한 동작이 가능하다. 본 논문은 이러한 기존 알고리즘의 단점을 보완하기 위하여, 고차 다항식의 계수 값을 반데몬드 행렬(Vandemond Matrix)에 SVD분해(Singular Value Decomposition)와 QR분해법(QR Decomposition)을 적용하여 행렬의 고유치와 직교성분만으로 연산하였다 또한, 입력 데이터의 구간을 분할하여 각 구간의 다항식을 생성하고, 새롭게 생성된 다항식을 이용하여 곡선 접합을 수행하도록 하였다. 입력 데이터와 곡선 접합결과의 평균제곱오차(Mean Square Error: MSE)와 표준편차(Standard Deviation: STD)를 통한 오차율 비교 결과 최하위 비트(Least Significant Bit: LSB) 에러 범위에서 MSE가 약 $10^{-9}$ 이고 STD는 약 $10^{-5}$로 정밀도가 향상되었다.

• 한국통신학회논문지
• /
• 제19권6호
• /
• pp.1095-1106
• /
• 1994

본 논문에서는 최소자승오차법(LMSE, least mean square error)을 이용하여 function processing(FP) 형태학 필터를 최적화하는 알고리즘을 제안한다. Erosion이나 dilation 연산들은 원하는 신호와 실제 필터의 출력 신호 사이의 평균자승오차(MSE, mean square error)를 최소화하는 농담(農談) 구조요소(GSE. grayscale structuring element)를 결정함으로써 최적화 된다. 본 논문에서는 LMS 트레이닝 알고리즘을 형태학 필터의 최적화에 적용하기 위하여 스텝 사이즈 매개변수 n가 만족해야 하는 조건을 보이고, 이를 이용하여 erosion이나 dilation 형태학 필터들의 최적 GSE를 결정할 수 있음을 보였다. 또한, 본 논문에서는 행렬을 사용하여 복합 형상한 연산들을 소역 행열 연산자로 새롭게 정의하고, 이소역 연산들에 LMS 알고리즘과 back-propagation 알고리즘을 적용하여 복합 형태학 필터들을 최적화할 수 있음을 보였다. 실험 부분에서는 제안된 최적 형상학 필터들을 2-D 영상에 적용한 결과를 보였다.

• 전기전자학회논문지
• /
• 제17권2호
• /
• pp.145-150
• /
• 2013

본 논문에서 ICS(Interference Cancellation System) 중계기에서 간섭제거를 위한 새로운 CSS(Complex Signed-Signed) CMA(Constant Modulus Algorithm) 알고리즘을 제안한다. 중계기가 궤환 신호를 가질 때 CSS CMA 알고리즘은 궤환 경로로부터 간섭 신호를 제거하기 위한 디지털 신호 처리를 사용한 ICS 중계기에 대해 제안한다. 제안된 Complex Signed Signed CMA 알고리즘은 스텝 사이즈를 조절함에 따라 하드웨어 복잡도와 성능이 개선된다. 제안된 Complex Signed Signed CMA 알고리즘에서 스텝사이즈가 0.00043인 경우 수렴상태에서 평균 자승 에러는 기존 CMA 알고리즘보다 약 4dB정도 더 낮다. 그리고, 평균 자승 에러 -25dB를 기준으로 LMS(Least Mean Square)와 Signed LMS(Normalized Least Mean Square)보다 수렴회수가 1950 ~ 2150회 정도 줄어든다.

• ETRI Journal
• /
• 제45권3호
• /
• pp.379-393
• /
• 2023

Underwater communication (UWC) is widely used in coastal surveillance and early warning systems. Precise channel estimation is vital for efficient and reliable UWC. The sparse direct-adaptive filtering algorithms have become popular in UWC. Herein, we present an improved adaptive convex-combination method for the identification of sparse structures using a reweighted normalized leastmean-square (RNLMS) algorithm. Moreover, to make RNLMS algorithm independent of the reweighted l₁-norm parameter, a modified sparsity-aware adaptive zero-attracting RNLMS (AZA-RNLMS) algorithm is introduced to ensure accurate modeling. In addition, we present a quantitative analysis of this algorithm to evaluate the convergence speed and accuracy. Furthermore, we derive an excess mean-square-error expression that proves that the AZA-RNLMS algorithm performs better for the harsh underwater channel. The measured data from the experimental channel of SPACE08 is used for simulation, and results are presented to verify the performance of the proposed algorithm. The simulation results confirm that the proposed algorithm for underwater channel estimation performs better than the earlier schemes.