• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.3 s.174
• /
• pp.794-802
• /
• 2000

Since the examination of CTOD problem revealed that the discrepancy among CTOD's was a matte., of definition, the relationships among parameters based on different definitions have been studied Particularly, the relationship between $\sigma$BS R-curve based on BS 7448 and R-curve based on the recently introduced $\sigma$5 parameter was investigated in this research. For the comparison, compact tension specimens of used 1Cr-0.5Mo steel, heat treated 1Cr-0.5Mo steel to mimic the new one, A12024-T6, and A12024-T351 were prepared and tested. Consequently, the relationship between $\sigma$5 and $\sigma$BS R-curves for tested materials were established by shifting the rotational center which could determined by rotation factor and ligament size.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2010.04a
• /
• pp.10-15
• /
• 2010

1996년 국내 6시그마 활동이 도입된 이후 제조업, 서비스업, 대기업, 중소기업, 공공기관등 모든 부문에서 활발히 추진되어 괄목할 만한 개선 성과를 이루었으나, 국방군수 분야인 정비분야에서는 그 활동이 지지부진 하였다. 이에 국방 군수 효율화 운동의 일환으로 2009년 육군종합정비창에서 시범적으로 실시한 6시그마 도입활동을 소개하고 보다 발전적인 방향을 모색함으로써 국방 군수경영 혁신에 기여 하고자 한다.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.573-578
• /
• 2009

Survey shows that temperature accounts for 90.6% of dissatisfaction in general hospital environment. In order to improve this situation, operation and thermal data of S hospital collected in 2006 are analyzed. The objective of this study is to find optimum fiducial temperature that minimizes occupants' complaints using 6 sigma method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.645-650
• /
• 2002

In this paper, new concept, low noise axial fan was developed. The fan was designed to operate at high-pressure condition inside the refrigerator. This fan - we call it Alpha fan - has small turbo blades at trailing edge of axial fan. These turbo blades make alpha fan operate at high pressure and low noise condition. In order to find out the optimal value of design parameters, 6-sigma method was used. The design parameters are ratio between inner and outer diameter, Height, Install angle and Install position of turbo blade. Optimal value of turbo blade was found out and the noise generated from this fan is reduced about 3dB(A).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.9 no.2
• /
• pp.143-150
• /
• 1976

A trial has been made to find out a new method of calculating the survival rate of a fish Population utilizing the length composition data and the characteristics of the frequency curve of the length which usually is normal distribution curve. In this paper, a stochastic method is introduced and applied to calculate the survival rate of yellow croaker caught by Korean trawlers in the Yellow Sea and the East China Sea in 1971. The results are as follows : Mean of survival rate 0.46089 Variance 0.03073 Standard deviation 0.17529 95 percent confidence interval 0.36040-0.56138.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.1
• /
• pp.104-110
• /
• 2006

The advantage of the DSM which employ multi-bit quantizer is the increased SNR at the modulator's output. Typically 6 dB improvement is effected for every one additional bit. But multi-bit quantizer evidently requires multi-bit DAC in the feedback loop. The integral linearity error of the feedback DAC has direct impact upon the system performance and degraded SNR of the system. In order to mitigate the negative impact the DAC has on the system performance, many DEM(Dynamic Element Matching) schemes has been proposed. Among the proposed schemes, four schemes(DER,CLA,ILA,DWA) are explained and its performance has been compared. DWA(Data Weighted Averaging) method shows the best performance of the all.

• Journal of Korea Multimedia Society
• /
• v.21 no.6
• /
• pp.685-697
• /
• 2018

(Most companies that perform BPR have not achieved satisfactory results or have not performed successful BPRs. There are many reasons for this, but the most important one has caused problems that do not accurately reflect the requirements of various stakeholders. In this paper, we will apply the BPR consulting methodology to a new value innovation requirements engineering process based on the Blue Ocean strategy, which is a way to create a new market without competition by customerizing potential customers by satisfying new customer expectations and needs. This paper uses a requirements engineering process that can generate customer value by applying the ERRC(Erasure Reduce Raise Create) analysis method, which is the core of the Blue Ocean Strategy Framework[1,2]. We will also apply the Six Sigma DFSS (Design For Six Sigma) methodology to improve quality and process through quantitative and systematic analysis. The proposed approach was presented to the BPR consulting to present a practical case, and the results of the empirical analysis of the system user to validate the results of BPR consulting.

• Journal of Astronomy and Space Sciences
• /
• v.22 no.4
• /
• pp.393-408
• /
• 2005

We developed and compared two automatic algorithms for moving object detections in the YSTAR-NEOPAT sky survey program. One method, called starlist comparison method, is to identify moving object candidates by comparing the photometry data tables from successive images. Another method, called image subtraction method, is to identify the candidates by subtracting one image from another which isolates sources moving against background stars. The efficiency and accuracy of these algorithms have been tested using actual survey data from the YSTAR-NEOPAT telescope system. For the detected candidates, we performed eyeball inspection of animated images to confirm validity of asteroid detections. Main conclusions include followings. First, the optical distortion in the YSTAR-NEOPAT wide-field images can be properly corrected by comparison with USNO-B1.0 catalog and the astrometric accuracy can be preserved at around 1.5 arcsec. Secondly, image subtraction provides more robust and accurate detection of moving objects. For two different thresholds of 2.0 and $4.0\sigma$, image subtraction method uncovered 34 and 12 candidates and most of them are confirmed to be real. Starlist comparison method detected many more candidates, 60 and 6 for each threshold level, but nearly half of them turned out to be false detections.

• Smart Structures and Systems
• /
• v.14 no.6
• /
• pp.1105-1129
• /
• 2014

The unscented Kalman filter (UKF) has been developed for nonlinear model parametric identification, and it assumes that the model parameters are symmetrically distributed about their mean values without any constrains. However, the parameters in many applications are confined within certain ranges to make sense physically. In this paper, a constrained unscented Kalman filter (CUKF) algorithm is proposed to improve accuracy of numerical substructure modeling in hybrid testing. During hybrid testing, the numerical models of numerical substructures which are assumed identical to the physical substructures are updated online with the CUKF approach based on the measurement data from physical substructures. The CUKF method adopts sigma points (i.e., sample points) projecting strategy, with which the positions and weights of sigma points violating constraints are modified. The effectiveness of the proposed hybrid testing method is verified by pure numerical simulation and real-time as well as slower hybrid tests with nonlinear specimens. The results show that the new method has better accuracy compared to conventional hybrid testing with fixed numerical model and hybrid testing based on model updating with UKF.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.2
• /
• pp.108-115
• /
• 1999

This paper proposes the robot inverse calibration method using a neural networks. A highorder networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from $\pm$3 to $\pm$0.1.