• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.487-490
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• 1995

This paper discisses the effects geometric errors on the measurement of error motions of rotor with the cylindrical capacitive displacement sensor. Analytic model of the measuring process with this sensor is derived and this model shows that the effect of geometric errors of sensor is larger than that of rator on the measurement of error motions of rotor. The computer simulation shows effect of periodic errors in this sensor on the measuring orbit.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.900-904
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• 1997

A problem in the grinding process using the machining center(MC) with a small diametric wheel is the machining error due to due to decrease of quill diameter. In this paper, a side-cut grinding is performed with a vitrified bonded CBN wheel by the MC, and the relation between grinding force and machining error for grinding conditions is investigated experimentally. It is show that the normal force has a significant effect on the machining error.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.167-167
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• 2000

This study aims at the development of REC sensor causing the gauge error in the hot strip rolling process, and the improvement of the hydraulic AGC (Automatic Gauge Control) system. The gauge error outbreaks from the various reasons, however, mainly the roll eccentricity is considered to cause a such kind of error. In the study, the REC (Roll Eccentricity Control System) sensor is designed using sensor An On - line test of the system shows the comprehensive effects of controlling the gauge error of the hot strip. On - Line test shows the possibility of enhancing the accuracy for gauge.

• 대한전자공학회논문지SP
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• 제41권3호
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• pp.111-120
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• 2004

본 논문에서는 경계 영역에서의 색번짐 현상을 줄이기 위한 벡터 오차 확산법을 제안한다. 이러한 결점은 양자화 과정에서 생기는 큰 누적된 양자화 오차의 확산으로 인해서 발성하게 되며, 특히 색이 변하게 되는 영상의 경계 영역에서 특정 칼라띠를 형성하게된다. 따라서 이러한 결점을 줄이기 위해서 세안한 벡터 오차 확산 방법은 오차를 확산 받은 벡터와 8개의 기준색과의 벡터 크기 및 벡터 각을 비교함으로써, 큰 양자화 오차를 전체 중간조 처리 과정에서 제외한다. 먼저 오차가 보정된 벡터의 크기가 8개의 기준색보다 클 경우 양자화 오차를 확산시키지 않게 되며, 벡터 각이 클 경우에도 양자화 오차를 확산 시키지 않는다. 그러므로 제안한 방법은 각 채널의 상관관계를 고려한 벡터 칼라 공간상에서 중간조 처리를 함으로써 시각적으로 색이 향상된 결과를 얻을 수 있었고, 경계 부분에서의 색번짐 현상도 줄일 수 있었다.

• 치과방사선
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• 제18권1호
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• pp.13-25
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• 1988

Bone destruction was induced experimentally by the insertion of a bit of the arsenic compound into the pulp chambers of the right premolars and the artificial bone defects were produced in the periapical regions of the left premolars in 7 dogs. The serial standardized periapical radiographs using aluminum stepwedge attached to the XCP instruments, and resin bite blocks were taken following insertion of arsenic compound and at 2, 4, 7, 10, 14, 17, 21, 24 and 28 days in case of bone destruction and following bone injury and weekly thereafter for a total of 14 weeks in case of bone formation. The errors of the method were determined with error estimators described by the Duinkerke. All radiographs were evaluated by the visual examination after joint evaluation by three dental radiologists and analysed with densitometer. The following results were obtained; 1. Analysis of the bone destruction process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.04㎜, S.D. for the over-all error; 0.06㎜, S.D. for the positioning error; 0.05㎜) 2) The radiographic changes were observed after 7 days in 6 cases, 4 days in 1 case and 10 days in 1 case by the visual examination. 3) Aluminum equivalent values were diminished after 2 days and the diminution of 0.58±0.19㎜ was demanded to be detected by the visual examination. 2. Analysis of the bone formation process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.03㎜, S.D. for the over-all error; 0.04㎜ S.D. for the positioning error; 0.04㎜) 2) The radiographic changes were observed after 2 weeks in 5 cases and 3 weeks in 2 cases by the visual examination. 3) Aluminum equivalent values were increased after 1 week and the increase of 0.45±0.15㎜ was demanded to be detected by the visual examination. 4) Aluminum equivalent values were increased continuously for 7 or 9 weeks but there as only extremely small change after 10 weeks.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.803-806
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• 1995

The vibration and nosic of gears is causeed by manufacting error,alignment error in assembly, and thr meshing stiffness of gears which changes periodically as the meshing of teeth process. On a pair of power transmission helical gears with profile error, the relation between the characteristics of gear vibration and the profile error type have been investigated by simulating the vibrational acceleration level and calculating the natural frequency. The results show that the profile error decrease the natural frequency by reducing the tool stiffness and that the concave error type increase the vibrationsl level. And this paper describes the effect of the tip relief on the vibrational acceleration level which a pair of helical gears with concave error generates.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1747-1750
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• 2003

This paper proposes a multilevel vector error diffusion for fast and accurate color reproduction. Proposed method considered both hue angle and Euclidean distance during the multilevel vector error diffusion procedure to improve time complexity and output image quality In the error diffusion process, it can be determined whether error is diffused or not by comparing the vector norm and lightness value between original vector and error corrected vector of neighborhood pixels. For adaptive selection of output patch, this paper computes chroma value of error corrected vector and compares the hue angle between error corrected input vector and 64 primary color vectors.

• 한국안전학회지
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• 제18권2호
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• pp.104-118
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• 2003

It has been criticized that conventional human reliability analysis (HRA) methodologies for probabilistic safety assessment (PSA) have been focused on the quantification of human error probability (HEP) without detailed analysis of human cognitive processes such as situation assessment or decision-making which are crticial to successful response to emergency situations. This paper introduces a new human reliability analysis (HRA) methodology, AGAPE-ET (A guidance And Procedure for Human Error Analysis for Emergency Tasks), focused on the qualitative error analysis of emergency tasks from the viewpoint of the performance of human cognitive function. The AGAPE-ET method is based on the simplified cognitive model and a taxonomy of influencing factors. By each cognitive function, error causes or error-likely situations have been identified considering the characteristics of the performance of each cognitive function and influencing mechanism of PIFs on the cognitive function. Then, overall human error analysis process is designed considering the cognitive demand of the required task. The application to an emergency task shows that the proposed method is useful to identify task vulnerabilities associated with the performance of emergency tasks.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.210-212
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• 1996

Random drift rate (i.e., random drift in angle rate) of a gyro represents the major error source of inertial navigation systems that are required to operate over long time intervals. It is uncorrectable and leads to an increase in the error with the passage of time. In this paper a technique is presented for analyzing random process from experimental data and the results are presented. The problem of estimating the a priori statistics of a random process is considered using time averages of experimental data. Time averages are calculated and used in the optimal data-processing techniques to determine the statistics of the random process. Therefore the contribution each component to the gyro drift process can be quantitatively measured by its statistics. The above techniques will be applied to actual gyro drift rate data with satisfactory results.

• Journal of the Korean Data and Information Science Society
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• 제18권4호
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• pp.963-972
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• 2007

When a control chart signals that a special cause is present, process engineers must initiate a search for and an identification of the special cause. Knowing the time of the process change could lead to identify the special cause more quickly, and to take the appropriate actions immediately to improve quality. In this paper, we propose the maximum likelihood estimator (MLE) for the process change point when a control chart is used in monitoring the parameters of a process in which the observations can be modeled as a first-order autoregressive(AR(1)) process plus an additional random error.