• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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• pp.406-414
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• 1995

자재절단문제를 일반적인 알고리즘을 사용하여 해결하였을 경우 패턴이 형 성되었을 때 계속되는 패턴에서 부품들이 연속하여 절단되 나오지 않게 된 다. 이와같이 부품이 연속되어 나오지 않는 경우를 부품이 단락 (discontinuity)되어진다고 이야기 한다. 이럴 경우 각 부품들은 원하는 주문 량만큼 절단되어 나올 때까지 생산라인에서 대기하고 있어야 한다. 따라서 생산라인에서는 절단된 모든 부품들을 임시적으로 적재해 놓아야 하므로 공 종소요가 증가하게 되고 절단공정이 혼잡해 지게 된다. 이를 볼때 절단되어 나오는 부품들이 계속되는 패턴에서 연속적으로 절단되어지게 하는 것이 중 요하다. 이와같이 부품들이 단락되어지지 않고 연속적으로 생산되면 공정소 요를 줄일수 있게 될 뿐 아니라 생산성의 향상을 기할수 있게 될 것이다.

• Journal of Scientific & Technological Knowledge Infrastructure
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• s.5
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• pp.20-30
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• 2001

컴퓨터를 쓰면 연속절단면 영상을 쌓아서 3차원 영상으로 재구성한 다음에 3차원 영상을 잘라 볼 수 있고 3차원 영상의 일부를 골라서 돌려 볼 수 있다[1,2]. 이처럼 사람 몸의 연속절단면 영상과 3차원 영상이 있으면 의과대학 학생과 일반인이 의학을 공부하는 데 도움이 된다(그림 1,2)[1-8,9].

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.15-24
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• 2011

Recently various anatomic researches by using serially sectioned images in VK(Visible Korean) project are in progress. In that sense, it is very important and necessary to represent images which keep information of the original anatomic images. In this regard, there are some studies to get rid of slice patterns in coronal and sagittal images. However, according to the rapid spatial frequency changes, the ringing effect occurred in common. In addition, because of merge with the original images which have splice patterns, those patterns appeared again. Therefore, in this study we found effective color space to apply to FFT(Fast Fourier Transform) and notch filter in getting rid of the slice patterns. To verify this, we used RGB, LAB, CMYK, HSV and HSL color space. Secondly we got rid of and alleviated the ringing effect by improving notch filter. To verify this, we compared proposed method with previous study on the basis of original images by visual method and objective values. These result images are expected to contribute to anatomy research in relation to VK project.

• Korea Science and Art Forum
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• v.25
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• pp.379-388
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• 2016

There are some studies to get rid of slice patterns in coronal and sagittal images by FFT(Fast Fourier Transform) and Notch filter. However, the use of a notch filter is the ringing effect according to the rapid frequency change occurs in common. Therefore, this study will be to evaluate the shape and effect of the notch filter. In addition, it is proposed a new notch filter design. Results of the study are as follows. First, Emission-Notch filter was relatively naturally correcting the cutting pattern. Second, Emission-Notch filter to use as Ringing effect is reduced relatively. The next through these findings and further research progress more completely removed the Ringing effect, and expects to reproduce the data close to the actual human body information.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.101-105
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• 2011

In most shipbuilding company, cutting procedure is proceed by cutting machine which run by CNC(Computer Numerical Code) data. In our cutting process, all CNC data is created by our nesting post processor system automatically. Among them, in case that cutting piece in the remnant plate, our system creates only one piece CNC data. Because remnant plate is not typical shape, and ship designers don't know remnant plate shape and quantity. In can happen some merit and good point if we modify 1:1 piece NC data by shorten cutting path, reducing cutting time or re-arrangement piece. For modifying cutting data, outside workers have to call to ship designer or have to go to NC control room where control the CNC system and cutting machine. It makes stop work process, and it waste time. In this paper, we introduce a program that can modify and replace 1:1 NC data with continuous or common NC data automatically.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.910-915
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• 2004

The objective of this study is to investigate the influence of process parameters, such as power of laser, travel speed of laser and material thickness, on the practical cutting region and the kerfwidth for the case of cutting of CSP 1N sheet using high power Nd:YAG laser with continuous wave(CW). In order to find the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and travel speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth for the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensional accuracy of the cut area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.11B
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• pp.1847-1857
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• 2000

통신의 연속적인 경로를 구성하기 위하여 광케이블의 상호접속점이 존재한다. 광섬유를 접속하는 과정에서, 두 광섬유 코어의 중심 축이 일치하지 않아 광 손실이 발생하게 되는데, 본 논문에서는 광섬유의 절단면의 형태에 따라 score, lip, roll off, chip, end angle, valley 모양으로 분류하고, 그 손실관계를 비교 분석하여, 광섬유의 절단면 불량으로 인한 재접속을 줄이기 위하여 불량여부를 쉽게 판정할 수 있는 융착접속 화면 개선 모델과 절단면의 형태별 접속허용 판정기준을 제시하였다.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.357-370
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• 2022

In this paper, Tobit and Heckit models are introduced. These models have been used for analyzing censored data. Censoring occurs at a specific point and a large number of observations are distributed with a positive probability at a certain point. Censoring can occur due to observing limitation or exogenous variables. Tobit and Heckit models are used to correct sample selection bias, which can occur when an ordinary linear regression model is fitted to censored data. However, the difference between the two models is not clearly accounted for; hence, they have often been used interchangeably. Therefore, the suitability of the models was validated through simulated data, and demonstrated through real data. As the result, it was confirmed that both Tobit and Heckit models are well-fitted to the data censored due to observing limitation, although Tobit model was fitted parsimoniously. In contrast, only Heckit model is well-fitted to the data censored due to exogenous variables.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.19-26
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• 2005

The objective of this study is to investigate the influence of process parameters, such as power of laser, cutting speed of laser and material thickness, on the practical cutting region and the kerfwidth fer the case of cutting of CSP IN sheet using high power Nd:YAC laser in continuous wave(CW) mode. In order to obtain the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and cutting speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth fur the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensionalaccuracyofthecutarea.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.519-526
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• 2000

This study is to investigate the recurrence possibility of consecutive dry years such as the long dry period around 1900 in the annual rainfall data at Seoul station. The truncation levels, as the criterion for the dry years, are decided such as to make the occurrence of dry years follow the Poissonian distribution, which assures independent occurrence of dry years. For the truncation level of mean-0.5stdv, the occurrence of dry years is found to satisfy the Poissonian distribution weakly with 99% significance level, but for those of mean-0.75stdv and mean-stdv with 95% significance level. For these truncation levels, the long dry period around 1900 is divided into several short consecutive dry years. The Poisson process has then been applied to derive the occurrence probability of consecutive dry years. For the truncation level of mean-0.75stdv or below, the Poisson process was found to reproduce similar occurrence probabilities to the observed. Especially for the lowest truncation level used in the study (mean-stdv), we could see that the occurrence probability of consecutive dry years estimated for the data collected before the long dry period around 1900 was higher that those for the data collected after the long dry period, thus, it could be concluded that the possibility of long dry periods is decreasing recently.cently.