• Journal of Korean Society for Quality Management
• /
• v.38 no.3
• /
• pp.408-412
• /
• 2010

In this note, we deal with a design problem for determining the levels of noise factors in the Taguchi method. Recently, Ree(2009) proposed a new method to determine the levels of noise factors that is dependent on the distribution of the noise factors. We discuss the original suggestion from Taguchi method, propose a way to compare the two methods and investigate the performance(mean square error) of two proposals by examples.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.61-62
• /
• 2006

A new neural network classifier is proposed for the automatic real-time surface inspection of high-speed cold steel strips having 11 different types of defects. 46 geometrical and gray-level features are extracted for the defect classification. 3241 samples of Posco's Kwangyang steel factory are used for training and testing the neural network classifier. The developed classifier produces plausible 15% error rate which is much better than 20-30% error rate of human vision inspection adopted in most of domestic steel factories.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.5
• /
• pp.21-26
• /
• 2005

It is important to measure the rotational accuracy of NC lathe spindle as it affects to the qualities of all machines machined by the NC lathe using in industries. The bad rotational accuracy of NC lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of NC lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental appratus for measuring of rotational accuracy by using eddy current type gap sensors, converters, screw terminal, data acquisition board inserted in computer and software f3r data acquisition, DT VEE ver. 5.0 and then error data acquired in the rotational accuracy test of NC lathe spindle are analysed in plots and statistical treatments.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.4 s.193
• /
• pp.76-83
• /
• 2007

A new neural network classifier is proposed for the automatic real-time surface inspection of high-speed cold steel strips having 11 different types of defects. 46 geometrical and gray-level features are extracted for the defect classification. 3241 samples of Posco's Kwangyang steel factory are used for training and testing the neural network classifier. The developed classifier produces plausible 15% error rate which is much better than 20-30% error rate of human vision inspection adopted in most of domestic steel factories.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2001.06a
• /
• pp.9-12
• /
• 2001

In DS/CDMA system the number of output signal levels increases as multi-channel signals are summed, hence the power amplifier with high linearity is required. PW/CDMA is a transmission technique that performs pulse width modulation on the multilevel signal synthesized from multiple channel data. In PW/CDMA system the signal level is maintained to be binary, hence the modulation and demodulation circuits become simple. In this paper we derive the probability of bit error of the PW/CDMA system in AWGN environment. The results are compared with DS/CDMA system and are verified through the computer simulations.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.148-150
• /
• 1988

The output characteristics of VSI by transistor depend upon bias signal with drive circuit. As the CTI is one of the VSI, takes case PWM output voltage. This Inverter operation is based upon position and negative of sinusoldal PWM signal by carrier triangular wave and compared sine one. Besides, the Inverter operation system required digital signal for microprocessor, sampling method of Inverter driver signals study for get rid of generated signal is error. In the paper, the method of 3 level PWM signal for CTI was studied. This method of signals depend upon caculated switching position of natural sampling with $10^{-6}$ modulation error for time flowchart programs.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.3
• /
• pp.163-172
• /
• 2003

A stereo matching has been an important tool for the reconstruction of 3D terrain. The current state of stereo matching technology has reached the level where a very elaborate DEM(Digital Elevation Map) can be obtained. However, there still exist many factors causing DEM error in stereo matching. This paper propose a new method to reduce the error caused by the lack of significant features in the correlation window The proposed algorithm keeps the correlation window as small as possible, as long as there is a significant feature in the window. Experimental results indicate that the proposed method increases the DEM accuracy by $72.65\%$ in the plain area and $41.96\%$ in the mountain area over the conventional scheme. Comparisons with Kanade's result show that the proposed method eliminates spike type of errors more efficiently than Kanade's adaptive window technique and produces reliable DEM.

• Proceedings of the KIEE Conference
• /
• 1998.07b
• /
• pp.423-425
• /
• 1998

In this paper, a novel Programmable Signal Conditioner(PSC) for Thermo Couple(T/C) without variable-resistance is proposed. It is fabricated by using a fully digitalized error-correction and calibration algorithm. In signal processing of T/C, since the output voltage of T/C is nonlinear and its level is very low, the circuitry become very complicated to reduce the converting error and identify the true thermal voltage signal. The newly proposed PSC has compensation and calibration algorithm not using variable resistor. Moreover structure can be very simple and it has highly precise output characteristics.

• International Journal of Aerospace System Engineering
• /
• v.5 no.1
• /
• pp.9-18
• /
• 2018

The longitudinal flight parameters of a light airplane are estimated from flight test data by use of the output error method. The reliability of the flight test measurement is examined in engineering judgment, scatter and Cramer-Rao bound, which turns out to be satisfactory with minor defects. Estimated parameter values are validated by comparing the simulated responses with the ones from actual flight tests. The FTD(Flight Training Device) of a light airplane turns out to satisfy the qualification of FAA Level 5 FTD in longitudinal motion. All the necessary practices for generation of high-fidelity data in longitudinal motion of a light aircraft are successfully performed in this study.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.26 no.5
• /
• pp.240-246
• /
• 2014

A fault detector was developed for heat exchangers of a hybrid heat pump (HP) for household. The proposed detector can be applied directly to raw operating data. It is to monitor a tracking error between a measured saturation temperature and its state observer. The observer was estimated from a state-space model simulating dynamics of a heat exchanger. The real hybrid HP was substituted with a dynamic simulator that implemented two-phased heat transfer and was validated by experimental data. And artificial fault data were generated using the simulator. Diagnosing the data showed the following. The residual calculated from the state observer error shows a relatively robust consistency with respect fouling level. The fault detector is practically useful because it detects a threshold fouling beyond which the performance starts to deteriorate significantly.