• 한국전기전자재료학회논문지
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• 제27권6호
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• pp.407-416
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• 2014

Five factors are identified, which affect the performance of optical filter: 1) type of optical glass, 2) existence of Fe, 3) photo pic coating type, 4) coating form, and 5) coating thickness. If we consider all the levels of five factors, there are 360 possible candidates. We determined five evaluation criteria, which can be used to evaluate possible candidates. For the performance measures we selected white-state avearge voltage, black-state average voltage, and black-state error rate. And we added economic criterion and quality and maintenance criterion. Through the two-step statistical analysis of white-state avearge voltage, black-state average voltage, and black-state error rates, we selected final four candidates. Based on the five criteria we finally determined optimal optical filter using AHP.

• Communications for Statistical Applications and Methods
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• 제16권2호
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• pp.239-347
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• 2009

신용평가모형의 판별력에 대한 검정방법으로 콜모고로프-스미르노프, 평균차이, AUROC, AR등과 같은 통계량이 널리 사용되고 있다. 이러한 통계량들의 판단기준은 정규분포 가정 하에서 평균차이를 기준으로 설정되었다. 본 연구에서는 모의 실험을 통해서 표본크기, 불량률 그리고 제II종 오류율을 고려하는 대안적인 판단기준을 제 안하고 현재 적용되고 있는 판단기준과 비교해본다. 또한 판별력 정도에 따른 각 통계량들의 의미를 10단계로 정의하고 모의 실험 결과와 현재 적용되고 있는 판단기준을 비교해 본다.

• 한국정밀공학회지
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• 제23권5호
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• pp.177-183
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• 2006

A tape feeder is an important feeding device to supply micro-chips such as 1005 and 0603 components to PCB in SMT process. Traditionally, tape feeding methods using sprocket wheel mechanism has been used for the pickup system of chip-mounters. However, there is growing needs for new feeding mechanism with high accuracy and confidence as electric components are getting much smaller. Thus, recently, a tape feeder using cam-slider mechanism is developed to meet such requirements. The major advantages of developed system are; significantly reduced indexing and backlash errors, slim and compact design, and improved repetitive capacity compared to existing system. In this paper, the performance evaluation criteria for the developed tape feeder are suggested. Stability against induced vibration, positioning accuracy, cycle time, durability and supply error rate are estimated using developed self testers. As a result, the excellence of developed tape feeding mechanism is validated using the effective rating methods.

• International Journal of Aeronautical and Space Sciences
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• 제17권2호
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• pp.253-259
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• 2016

The typical method for performing an absolute radiometric calibration of a Synthetic Aperture Radar (SAR) System is to analyze its response, without interference, to a target with a known Radar Cross Section (RCS). To minimize interference, an error-free calibration site for a Corner Reflector (CR) is required on a wide and flat plain or on an area without disturbance sources (such as ground objects). However, in reality, due to expense and lack of availability for long periods, it is difficult to identify such a site. An alternative solution is the use of a Triangular Trihedral Corner Reflector (TTCR) site, with a surrounding protection wall consisting of berms and a hollow. It is possible in this scenario, to create the minimum criteria for an effectively error-free site involving a conventional object-tip reflection applied to all beams. Sidelobe interference by the berm is considered to be the major disturbance factor. Total interference, including an object-tip reflection and a sidelobe interference, is analyzed experimentally with SAR images. The results provide a new guideline for the minimum criteria of TTCR site design that require, at least, the removal of all ground objects within the fifth sidelobe.

• 전기학회논문지
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• 제64권3호
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• pp.485-491
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• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.

• 응용통계연구
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• 제21권1호
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• pp.109-123
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• 2008

많은 소지역 추정량이 제안되었으며, 국내외에서 소지역 추정에 관한 많은 연구가 진행되고 있다. 또한 소지역 추정량의 특성과 우수성을 비교하기위한 비교통계량도 연구되고 있다. 기존의 소지역 추정량은 MSE(Mean square error)를 최소화하여 얻어지며, 이에 따라 추정량의 우수성도 MSE를 기준으로 판단하고 있다. 본 논문에서는 최근 새롭게 재조명 되고 있는 MSPE(Mean square percentage error)를 최소화하는 추정량을 제안하였다. 신기일 등 (2007)에서 사용된 비교통계량과 MSE 그리고 MSPB를 이용하여 제안된 추정량과 기존의 소지역 추정량을 비교하였다.

• 제어로봇시스템학회논문지
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• 제3권1호
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• pp.32-39
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• 1997

One of the most important performance criteria in tuning the gain of position loop controller for CNC machining center is the contour error. In this papre we analyze contour error in the linear and circular interpolations for the axis-matched and mismatched cases. To have small contour errors, it is necessary to set the P gain for each axis to be same. And the D gain should be much smaller than the P gain. Baded on the analysis in the frequency domain, we propose a gain tuning method for the P and PD controllers. We show that the PD controller is better than the P controller. The effectiveness of this method is demonstrated by experiments.

• 한국농공학회논문집
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• 제62권1호
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• pp.61-70
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• 2020

To estimate the ventilation volume of mechanically ventilated swine farms, various regression models were applied, and errors were compared to select the regression model that can best simulate actual data. Linear regression, linear spline, polynomial regression (degrees 2 and 3), logistic curve, generalized additive model (GAM), and gompertz curve were compared. Overfitting models were excluded even when the error rate was small. The evaluation criteria were root mean square error (RMSE) and mean absolute percentage error (MAPE). The evaluation results indicated that degree 3 exhibited the lowest error rate; however, an overestimation contradiction was observed in a certain section. The logistic curve was the most stable and superior to all the models. In the estimation of ventilation volume by all of the models, the estimated ventilation volume of the logistic curve was the smallest except for the model with a large error rate and the overestimated model.

• 대한인간공학회지
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• 제30권1호
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• pp.1-8
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• 2011

While human error has been one of the main technical issues from the early era of human factors engineering, it still remains hot and somewhat vague due to the various types of the concepts and words on human errors in practice. There may be some technical limitations hindering human error prevention activities. This paper introduces the human error activities described in the papers if this issue of ESK Journal according to a few criteria proposed for more effective technical review. And two basic technical issues are discussed on the concepts, perspectives, and classifications about human errors. Each activity shows its own artifacts associated with the safety purpose and the nature of the industry. This paper also provides a set of new technical bases proposed for a more effective management of human errors by considering the dependability, representativeness, and structuredness of human errors. Additionally, this paper includes some new challenges over the current prevention-oriented activities; positive utilizations of human errors to training/education, advertisements, fun and entertainments, and nudges.

• 전자공학회논문지S
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• 제35S권10호
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• pp.175-185
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• 1998

본 논문에서는 Adams에 의해 제안된 제한된 최소 자승 오차 기준에 의한 FIR 필터 설계 방법을 기초로 하여 저역 통과 필터 외의 다른 여러 가지 필터를 설계할 수 있는 방법론을 제시하였다. 이 방법에 의한 설계는 기존의 자승 오차 최소화 방법과 최대 오차 최소화 방법의 혼합된 형태로써 오차 기준으로 자승 오차와 최대 오차 두 가지를 동시에 고려하게 되며, 최고 이득, 전이 대역폭, 자승 오차 세가지가 모두 만족될 때만 그 해 즉, 임펄스 응답을 찾을 수 있게 된다. 이때 최적화 과정에서는 다중 교환 알고리즘을 이용하였다. 본 논문은 위의 두 중요 오차 기준의 상호 보완을 통하여 다중 대역 통과 필터, 미분기 및 Hilbert 변환기등의 최적 설계에 적용할 수 있는 방법에 대해 고찰하였으며, 그 결과 제한된 최소 자승 오차 기준에 의한 설계 방법이 단순한 저역 통과 필터 뿐만이 아니라 여러 가지 다양한 FIR 필터 설계에 있어서도 그 우수함을 증명할 수 있었다.