• 한국생산제조학회지
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• 제23권1호
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• pp.94-101
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• 2014

Recently, in order to reduce the time required to replace an optical jumper cord, many researchers are using a field-installable connector and applying the ferrule polishing method, ferrule mechanical contact method, or ferrule fusion contact method. However, the process of arranging the length of the optical fiber, i.e., inserting the optical fiber into the ferrule by hand and checking its cross section, takes 60% of the time required for the entire process, which increases the overall cost. Therefore, in order to make this task more cost-effective, we will develop an automated inspection system with automatic cross-sectional arrangement of a field-installable connector. This system will be able to decrease the failure rate from 10% to 2% compared with the conventional method when cutting the optical fiber inserted into the ferrule. It will also improve the productivity by decreasing the test time by 28% compared with the conventional method. Our studies showed that it was possible to reduce the production costs and improve the quality of a field-installable connector, and we expect it to dominate the market.

• Nuclear Engineering and Technology
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• 제54권7호
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• pp.2592-2598
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• 2022

Research groups in the field of PET instrumentation are studying time-of-flight(TOF) technology to improve the signal-to-noise ratio of PET images. Scintillation light transport and collection plays an important role in improving the coincidence resolving time(CRT) of PET detector based on a pixelated crystal array. Four crystal arrays were designed by the different optical reflection configuration such as external reflectors and surface treatment on the CRT and compared with the light output, energy resolution and CRT. The design proposed in the study was composed of 8 × 8 LYSO crystal array consisted of 3 × 3 × 15 mm³ pixels. The entrance side was roughened while the other five surfaces were polished. Four sides of all crystal pixels were wrapped with ESR-film, and the entrance surface was covered by Teflon-tape. The design provided an excellent timing resolution of 210 ps and improved the CRT by 16% compared to the conventional method using a polishing treatment and ESR-film. This study provided a method for improving the light output and CRT of a pixelated scintillation crystal-based brain TOF PET detector. The proposed configuration might be an attractive detector design for TOF brain PET requiring fast timing performance with high cost-effectiveness.

• 한국건축시공학회지
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• 제24권1호
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• pp.77-86
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• 2024

본 연구에서는 폴리우레아 도막방수재의 시공 시차별 분석과 열화면에 대한 유지관리 시공 타입별 분석을 통해 시공 이음부위의 적정 시공 방안을 제시하고자 전체 16가지 조건을 대상으로 시공 이음부위에 대한 평가를 진행하였다. 결과 분석을 통해 시공시차가 길어지면 길어질수록 이음부를 통한 누수발생률은 증가하는 것으로 분석되었고, 프라이머 시공을 통해 누수 예방이 가능한 것으로 확인되었다. 또한 장시간 옥외 노출된 폴리우레아는 표면이 열화되어 약해진 상태이기 때문에 해당 부위를 연마할 경우 표면손상이 확대되어 계면 형성에 영향을 미치는 것으로 분석되어, 유지관리 시공 시에는 프라이머를 도포하고 시공하는 것이 바람직하겠으며, 동일한 우레아 계열의 재료를 시공하는 것이 방수 안정성을 확보할 수 있을 것으로 판단된다.

• 한국세라믹학회지
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• 제46권3호
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• pp.288-294
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• 2009

The platelet AlO(OH) nano colloids were prepared by hydrothermal reaction of the $\gamma-Al_2O_3$ obtained with dehydration of $\gamma$-AlO(OH) and dilute $CH_3COOH$ solution. In hydrothermal reaction process, reversible reaction was accompanied between $\gamma-Al_2O_3$ and AlO(OH), and hydrothermal reaction temperature, hydrothermal reaction time and $CH_3COOH$ concentration had an effect on the crystal structure, surface chemical property, surface area, pore characteristics and crystal morphology of the AlO(OH) nano colloid particles. In this study, it was investigated to the hydrothermal reaction condition of the AlO(OH) nano colloid for using catalyst support, heat resisting agent, adsorbents, binder, polishing agent and coating agent. The crystal structure, surface area, pore volume and pore size of the platelet AlO(OH) nano colloids were investigated by XRD, TEM, TG/DTA, FT-IR and $N_2$ BET method in liquid nitrogen temperature.

• 상하수도학회지
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• 제18권4호
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• pp.486-492
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• 2004

CMP (Chemical mechanical polishing) is inevitable process to overcome $0.2{\mu}m$ wire thickness in semiconductor industry. In this study, effect of pressure to separate used CMP slurry into solid and liquid for recycle and reuse by ultrafiltration was investigated. Also, water quality after the ultrafiltration such as turbidity and TDS was evaluated. The material of membrane used in the study was PVDF. The used CMP contained 0.5% of solid content and then concentrated up to 18% by weight. The used CMP can not be concentrated higher than 18% because of viscosity and abrasion of pump. The tested feed pressures were 22.1, 29.4 and 36.8 psi. The results have shown that operating at 36.8 psi has advantages on operation time and total flux. The specific flux showed some variation at 1 to 15 of concentration factor but no difference after 15 of concentration factor. Mass balance of solid at initial stage of the operation showed some unbalance because of deposition of solid on the membrane, which was main reason to reduce flux. Turbidity was very stable at lower than 0.2NTU for 22.1 and 36.8 psi of feed pressure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1294-1298
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• 2005

In this study, combined micro press and surface finishing process are proposed to fabricate the micro nozzle array on a stainless steel sheet metal. In micro hole punching process the burr occurs inevitably, but the burr must be minimized in order to improve the quality and accuracy of the product. For this reason, subsequent magnetic field-assisted finishing technique is applied to remove the burr which exists around the nozzles for ink-jet printer head and proved to be a feasible for deburring by experiment. The deburring characteristics of sheet metals were investigated changing with polishing time and magnetic abrasive size. After the deburring, the burr size has remarkably reduced and roundness of the hole also has improved.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 추계학술발표논문집 (상)
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• pp.601-604
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• 2003

본 논문은 프로젝션 화면에서 사용자와 컴퓨터간의 상호작용을 위한 인터페이스인 리바이저를 제안한다. 리바이저는 프로젝션 화면에서 사용자의 손 제스처로 문서교정 부호를 인식하여 전자문서를 교정하는 인터페이스 시스템이다. 프로젝션 화면에서 이러한 제스처를 인식하려면 두 가지 문제가 있다. 하나는 다양한 빛의 변화와 복잡한 배경을 가지는 프로젝션 화면에서 전방물체를 검출하는 것이고, 다른 하나는 사용자의 연속적인 움직임에서 사용자의 의도를 알아내는 것이다. 전방물체를 검출하기 위해 프로젝터로 입력되는 영상과 카메라에 의해 캡쳐된 영상 사이의 색상정보를 사용한다. 이 색상정보는 다양한 빛의 변화와 복잡한 배경에서 전방물체를 구별할 수 있게 한다. 연속된 제스처를 인식하기 위해 적출과 인식이 포함된 새로운 제스처 적출방법을 제안한다. 실험결과 제안된 시스템에서 의미없는 움직임이 포함된 제스처 시퀀스에서 사용자 제스처의 인식률은 평균 93.22%로 만족할만한 결과를 보였다.

• 한국광학회지
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• 제10권5호
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• pp.373-378
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• 1999

투명한 유전체 박막과 관련된 측정 분야는 반도체 산업의 발전과 함께 급속히 성장하고 있으며, 회로의 고집적화 추세에 맞추어 고정밀도의 측정 성능을 요구하고 있다. 최근 웨이퍼의 광역 평탄화를 위한 CMP(chemical mechanical polishing)공정의 도입으로 인하여 박막의 두께뿐만 아니라 미세 형상에 대한 측정 요구가 증가하고 있다. 이 논문에서는 기존의 비접촉 표면 형상 측정법의 하나인 백색광 주사 간섭법을 이용하여 박막의 두께 형상을 측정하여 새로운 측정 알고리즘 제시하고자 한다. 이 방법은 기존의 백색광 간섭 신호 해석법의 하나인 주파수 분석법과 비선형 최소 자승법을 이용함으로써 구현된다. 그리고 실험을 통하여 개발된 알고리즘의 타당성을 검증한다.

• 한국빅데이터학회지
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• 제4권2호
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• pp.61-71
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• 2019

반도체 웨이퍼의 표면을 연마하여 평탄화하는 Chemical Mechanical Planarization(CMP) 공정은 다양한 화학물질과 물리적인 기계장치에 의한 작용을 받기 때문에 공정을 안정적으로 관리하기 힘들다. CMP 공정에서 품질 지표로는 Material Removal Rate(MRR)를 많이 사용하고, CMP 공정의 안정적 관리를 위해서는 MRR을 예측하는 것이 중요하다. 본 연구에서는 머신러닝 기법들을 이용하여 CMP 공정에서 수집된 시계열 센서 데이터를 분석하여 MRR을 예측하는 모형과 공정 품질을 해석하기 위한 분류 모형을 개발한다. 나아가 분류 결과를 분석하여, CMP 공정 품질에 영향을 미치는 유의미한 변수를 파악하고 고품질을 유지하기 위한 공정 조건을 설명한다.

• 한국정밀공학회지
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• 제23권4호
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• pp.99-108
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• 2006

Since mold industries are regarded as belonging to three types of bad business, capable young people are reluctant to work in this field. The industries are hard to employ skilled workers who have much experience and knowledge On the mold manufacturing. Thus, effective CAM systems are required for unskilled workers to create process plans and NC data for the manufacturing, and process plans play important roles in the downstream manufacturing processes, such as NC machining, polishing, and final assembly. This study proposes a decision support system that facilitates unskilled workers to easily select high quality NC-data, as well as to increase productivity. The proposed system is assumed to follow a CAM operation scenario that consists of next three steps: 1) identifying several process plans and enumerating feasible unit machining operations (UMOs) from material and part surface information, 2) creating all feasible NC-data based on UMOs using a commercial CAM system, 3) selecting the best NC data among the feasible NC data using four screening criteria, such as machining accuracy, machining allowance, cutting load, and processing time. A case study on the machining of a camera core mold is provided to demonstrate the proposed system.