• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.05a
• /
• pp.311-311
• /
• 2004

1960년 레이저가 발명된 이래 레이저의 응용연구가 많은 비중을 차지하여 오늘날 다양한 방면에서 레이저가 필수적인 장치로 각광을 받게 되었다. 레이저의 특성들 중에서 특히 직진성, 에너지 집중도 및 고휘도성을 이용하여 용접, 절단, 각인 등의 산업적 응용에 많이 활용되고 있다 그 중 레이저가 보통의 빛과 같이 투명한 물체를 통과하고 특수한 렌즈를 이용하면 투명한 물체의 내부에 초점을 맞춰 크랙(crack)을 낼 수 있는 바 이를 이용하여 크리스탈이나 유리의 내부에 2차원 형상이나 3차원 형상을 각인시킬 수 있다.(중략)

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.05c
• /
• pp.145-148
• /
• 2002

본 논문에서는 관상동맥 질환의 객관적 분석을 위해, 혈관단면영상에서의 ROI(Lumen, Media, Plaque)에 대한 정확한 분할과 분할한 영역에서 질병을 유발시키는 요소들에 대한 정량적 분석을 위한 소프트웨어를 개발하였다. 본 시스템은 Visual C++ 6.0을 이용하여 개발하였으며, 현미경으로부터 획득한 관상동맥 단면영상에 적용하여 Lumen, Media와 Plaque를 분할하고, 각 영역의 형태학적 특징을 추출하여 분석 결과를 파일로 저장할 수 있도록 구현하였다. 분석된 결과는 심장질환의 객관적 진단을 위한 보조판단근거로써 사용될 것으로 기대한다.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2015.10a
• /
• pp.249-250
• /
• 2015

• Magazine of RCR
• /
• v.18 no.1
• /
• pp.45-53
• /
• 2023

• Convergence Security Journal
• /
• v.12 no.1
• /
• pp.9-16
• /
• 2012

Due to the large scale application of software systems, software reliability plays an important role in software developments. In this paper, a software reliability growth model (SRGM) is proposed for testing time. The testing time on the right is truncated in this model. The intensity function, mean-value function, reliability of the software, estimation of parameters and the special applications of Pareto NHPP model are discussed. This paper, a numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection, depended on difference between predictions and actual values, were efficient using the mean square error and $R_{SQ}$.

• Convergence Security Journal
• /
• v.11 no.4
• /
• pp.85-91
• /
• 2011

Due to the large-scale application software syslmls, software reliability, software development has animportantrole. In this paper, software truncated software reliability growth model was proposed based on log-logistic distribution. According to fixed time, the intensity function, the mean value function, the reliability was estimated and the parameter estimation used to maximum likelihood. In the empirical analysis, Poisson execution time model of the existiog model in this area and the log-logistic model were compared Because log-logistic model is more efficient in tems of reliability, in this area, the log-logistic model as an alternative 1D the existiog model also were able to confim that you can use.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.2
• /
• pp.106-113
• /
• 2002

Stencil is used normally as a mask for seeder pasting on pad of PCB. The objective of this study is to develop stencil cutting system and determine optimal conditions which make good-quality stencil by using a Nd:YAG laser. The effects of process parameters such as laser power, type of mask, gas pressure, cutting speed and pulse width old the cut edge quality were investigated. In order to analyse fille cut surface characteristics(roughness, kerf width, dross) optical microscopy, SEM photography and roughness test were used. As a result, the optimal conditions of process parameters were determined, and the practical feasibility of the proposed system is also examined by using a commercial Gerber file for PCB stencil manufacturing.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.4
• /
• pp.899-907
• /
• 1996

In this paper, we proposed an algorithm to eliminate false feature points to upgrade the system ability using the cross number method. By using the proposal algorithm, it was able to extract feature points exactly and increase the recognition rates.In the experiment, we used3 groups : the uncut-partially noised, and uncut completely noised fingerprint to verify our proposal. We then compared the results of the proposed system with those of another system in which false feature points were not eliminated. We have obtained good recognition rates of 97.7%, 97.7%, and95.0% in the cut, uncut-partially noised, and the uncut-completely noised fingerprints. However, the other system received the results of the cut 60%, the uncut-partially noised 35%, and the uncut-completely noised 50% respectively. As a result, we belive that the fingerprint may be recognized after adapting the proposal algorithm.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.7
• /
• pp.132-140
• /
• 2000

Plasma arc cutting is one of the most widely used processes in metal cutting fields and is a process that produces parted metal plates by cutting them with an arc plasma established between the electrode tip and the plate(workpiece). When the tip-to-workpiece distance varies during cutting, the cut quality, for example the kerf width, is deteriorated by the change of plasma arc. The variations of tip-to-workpiece distance are due to the different factors such as inaccuracies in setting the torch or workpiece, thermal distortions during cutting, and uneven surface of workpiece. The control to keep the tip-to-workpiece distance constant is thus indispensable to improve the flexibility of automatic plasma arc cutting system applications. In this study, an arc sensor which utilizes the electrical signal obtained from the plasma arc itself was developed. The arc sensor has an advantage that no particular sensing device is necessary and real-time sensing of the tip-to-workpiece distance is possible directly under the plasma arc. The relationship between plasma arc voltage and tip-to-workpiece distance was determined through the repeated experimental results. The model was used for developing an automatic tip-to-workpiece distance control system of plasma arc cutting. It could be shown that the proposed system has a successful capability of tip-to-workpiece distance control.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.2
• /
• pp.20-24
• /
• 2010

High speed cutting processes of rigid flexible printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also robust laser cutting system has been designed and developed in order to obtain a good cutting quality of rigid and flexible PCB with multi-layers (2-6 layers). Power controller module developed for ourselves is adapted to control the laser output power in the range less than 1%. The systems show the good performance of cutting speed, cutting width and cutting accuracy, respectively. Especially we have confirmed that the short circuit problem due to the carbonized contamination occurred in cross section of multi-layers by thermal effect of high power laser has been improved largely by using multi-pass cutting process with low power and high speed.