• 수산해양기술연구
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• 제51권4호
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• pp.545-552
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• 2015

The main object of this study is to investigate the collection characteristics of an electro-static multi-staged impaction system, experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as the inlet velocity, stage number, applied voltage and shape of discharge electrode, etc. In results, the pressure drop is shown below $148mmH_2O$ lower than that of the conventional bag filter at inlet velocity 3.46 m/s and 5 stage. For 5 stage, the collection efficiencies are to be 97.4, 99.0% with the applied voltage 0 kV at the inlet velocity 2.07, 3.46 m/s, while 98.4, 99.9% with 40 kV of a sharp edge discharge electrode. Additionally, the present system is to be considered as an effective compact system for a removal of particulate pollutants from marine diesel engines due to much higher collection efficiency and appropriate pressure drop.

• 한국컴퓨터산업학회논문지
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• 제10권5호
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• pp.187-192
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• 2009

본 논문에서 개개인의 인증을 위한 그래프 이론을 사용한 손등 표면의 정맥 패턴의 인식을 알고리즘을 제안하였다. 개인 고유의 손 정맥 패턴의 데이터이미지를 사용하여 우리는 기대되는 응답의 측정을 위한 그래프 이론의 틀 내에서 매칭 알고리즘을 사용했다. 전처리과정을 통해 캡쳐된 이미지는 좀 더 날카롭고 명료하게 변환하였으며 세선화하였다. 세선화 후 이 이미지는 다시 정규화하여 노드와 에지셀을 갖춘 그래프를 만들었다. 이 정규화된 그래프는 인접 매트릭스를 만들 수 있었으며, 개개인의 정맥 패턴으로 부터 각각의 인접 매트릭스는 달랐다. 우리는 개인의 정맥 패턴은 실험을 통해 생체인식의 새로운 방법으로 접근할 수 있었다.

• Tribology and Lubricants
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• 제21권4호
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• pp.185-192
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• 2005

The press cutter is productive equipment that practically manufactures mechanical components and polymer-based materials such as fabrics, papers, films, leathers, and rubbers into the desired shapes using a press cutting tool. The plate cutting process is one of the primary energy absorbing mechanisms in a grounding or collision event between a press cutter and a material on a die. The cutting mechanism is complicated and involves plastic flows of a plate in the vicinity of the tip, friction between the wedge and the plate, deformation of the plate. In this paper, we studied the effect of friction between cutter and plastic sheet far producing precise and superior products. In this paper, the press cutter is analyzed numerically using MARC finite element program for a optimization design of a press cutter. The FEM computed results show that the maximum von Mises stress is concentrated on the tip of a press cutter, which may lead to the edge wear or impact wear of the sharp cutter. Based on the FEM result and Taguchi's experimental design method, the optimized design model 9 for a press cutter is recommended as a best one.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.576-576
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• 2012

High quality single crystalline strain controlled wurtzite ZnO nanowire arrays have been grown on conductive silicon and ITO substrates by a facile hydrothermal method. The diameter of the nanowires was found to be less than 90 nm approximately for both of the two kinds of substrates. The quality of the ZnO nanowire arrays is dramatically improved by hanging the substrate above from the bottom of the Teflon lined autoclave. The structural investigation indicates the preferential orientation of the nanowire along c-axis. In order to make the convincible comparison, the photoluminescence property of the nanowire arrays grown under different conditions are measured, the sharp near band edge emission from PL, low turn-on voltage ($1.9V/{\mu}m$) from field emission measurement and Fowler-Nordheim plot was investigated from ZnO nanowire arrays grown by proposed substrate hanging method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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• pp.121-123
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• 2007

Foreign bodies with a sharp edge which are accidentally swallowed are likely to become lodged in the stomach. An animal study was undertaken to determine the outcome of orthodontic anchorage screw ingestion. The radiographic findings of ten Mongolian dogs that ingested a total of 10 orthodontic anchorage screws and 10 reamers (both a screw and a reamer per dog) were evaluated. The study showed that all orthodontic anchorage screws and reamers reaching the stomach spontaneously passed, with the exception of two reamers. Further investigation of clinical cases might be necessary to determine whether the results of our animal study are in accordance with clinical findings.

• 동아시아경상학회지
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• 제8권3호
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• pp.15-24
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• 2020

Purpose - New technologies allow service providers to integrate all the customer information within and between contact channels so that they can offer individualized services. The availability of new mobile devices enables retailers to interact with customers through countless channels (Rigby, 2011). The objective of this research is to examine customers' attitudes toward O2O (on-line to off-line) services and their intention to use based on the Technology Acceptance Model (TAM). Research design, data, and methodology - Utilizing the TAM model, the mediating effect of the users' attitudes toward O2O services on the relationship among perceived ease of use, perceived usefulness, perceived risks and intention to use are to be investigated. Results - The result shows that the perceived ease of use, perceived usefulness, perceived risks have a significant effect on customers' attitudes toward O2O services. It is also revealed that the attitude toward O2O services has a mediating effect among perceived ease of use, perceived usefulness, perceived risks and intention to use. Conclusions - The boundary between on-line and off-line is eroding and various services based on the O2O platform are growing. The results of this study and managerial implications can be applied to O2O platform operators or enterprises planning to sharp on their competitiveness edge through offering variations of service channels.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.158-163
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• 2002

This paper presents a multiple sensor system for rapid and high-precision coordinate data acquisition in the OMM (On-machine measurement) process. In this research, three sensors (touch probe, laser, and vision sensor) are integrated to obtain more accurate measuring results. The touch-type probe has high accuracy, but is time-consuming. Vision sensor can acquire many point data rapidly over a spatial range but its accuracy is less than other sensors. Also, it is not possible to acquire data for invisible areas. Laser sensor has medium accuracy and measuring speed among the sensors, and can acquire data for sharp or rounded edge and the features with very small holes and/or grooves. However, it has range- constraints to use because of its system structure. In this research, a new optimum sensor integration method for OMM is proposed by integrating the multiple-sensor to accomplish mote effective inspection planning. To verify the effectiveness of the proposed method, simulation and experimental works are performed, and the results are analyzed.

• 한국생산제조학회지
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• 제19권4호
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• pp.427-433
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• 2010

With recent increased demand for reverse engineering in dental machining, the 3D laser scanner is widely used for inspection of artificial pontic. In order to overcome the optical drawback of laser scanner, such as irregular scatter, direction of beam, and the influence of surface integrity, it is developed in this study a new 3D measuring system for artificial pontic using spherical coordinate system mechanism by point laser sensor, which keeps the direction of beam normal to surface consistently. The comprehensive integrated system is established to evaluate the improvement of accuracy with data acquisition system. The experimental results for measuring a master ball and pontic models shows the excellent form accuracy and repeatability compared with conventional apparatus. Also, these results shows the possibility to apply this system for the measuring purpose within 0.05mm accuracy of pontic at the sharp edge or margin contour, which was difficult to measure at the conventional systems.

• 천문학회지
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• 제36권3호
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• pp.123-144
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• 2003

The 8m class telescopes in the ground-based optical astronomy together with help from the ultra-sharp eye of the Hubble Space Telescope have enabled us to observe forming galaxies beyond red shift z = 5. In particular, more than twenty Ly$\alpha$-emitting galaxies have already been found at z > 5. These findings provide us with useful hints to investigate how galaxies formed and then evolved in the early universe. Further, detailed analysis of Ly$\alpha$ emission line profiles are useful in exploring the nature of the intergalactic medium because the trailing edge of cosmic reionization could be close to z $\~$ 6 -7, at which forming galaxies have been found recently. We also discuss the importance of superwinds from forming galaxies at high redshift, which has an intimate relationship between galaxies and the intergalactic medium. We then give a review of early cosmic star formation history based on recent progress in searching for Ly$\alpha$-emitting young galaxies beyond red shift 5.

• 한국전자파학회지:전자파기술
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• 제6권1호
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• pp.10-16
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• 1995

완전도체 스트립 회절격자에 의한 E-분극 산문제를 모멘트법을 이용하여 해석하였다. E분극의 경우는 청도 되는 표면전류밀도가 모서리 양 끝에서 매우 높을 것으로 추측된다. 이때 스트립에 청도되는 표면전류밀도는 차수가 0인 Ultraspherical 다항식의 급수와 적절한 모서리 경계조건을 만족하는 함수의 곱의 급수로 전개하였다. 전류밀도와 반사계수에 대한수직결과를 기존의 다른 수틀과 비교하였다. 본 논문의 수치결과가 기존의 다른 수를 사용했을 때 보다 기하학적 반사계수의 경도가 매우 빠르게 향상됨을 보였다. 기하학적 반사계수에서의 급변점 위치는 입사각, 스트립 폭 및 스트립 주기를 변화시킴으로써 이동시킬 수 있었다.