• 전자공학회논문지SC
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• 제46권6호
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• pp.14-20
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• 2009

영상 처리의 목표는 관찰자를 위하여 영상의 시각적인 측면을 개선하는 것이다. 히스토그램은 디지털 영상 처리의 기초 자료로 사용될 수 있는 중요한 도구이다. 그러므로 히스토그램을 효과적으로 관리하는 것은 디지털 영상 처리에 있어 매우 중요하다. 현재 머신 비전 검사 시스템은 여러 외관 검사 분야에서 사용되어지고 있다. 하지만 머신 비전 시스템에 의한 외관 검사 결과는 작업장의 조명에 의한 영향을 많이 받는다. 본 논문에서는 이러한 영향을 극복하기 위한 방법으로 히스토그램 변환을 이용해서 머신 비전 검사의 정확성을 향상시키는 방법을 제안하였다. 제안하는 방법은 영상 내에서 개선이 필요한 영역에 대한 히스토그램 변환을 수행함으로써, 이들 영역의 특징들을 향상시키는 효과를 거둘 수 있다. 본 논문에서 제안된 방법은 지그 플레이트의 외관 검사를 통해 검증하였다.

• The Journal of Advanced Prosthodontics
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• 제5권1호
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• pp.21-28
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• 2013

PURPOSE. This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS. Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at $30^{\circ}$ to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for $10^5$ cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (${\alpha}$=0.05). RESULTS. Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION. The abutment types did not have a significant influence on short term screw loosening. On the other hand, after $10^5$ cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not.

• 대한조선학회논문집
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• 제54권4호
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• pp.312-320
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• 2017

This paper deals with the development of structural test facility for the strength assessment of marine leisure boat built from carbon fiber reinforced plastics (CFRP) materials. The structural test facility consists of test jig, load application and control system, and data acquisition system. Test jig, and load application and control system are designed to accommodate various size and short span to depth ratios of single skin, top-hat stiffened and sandwich constructions in plated structural format such as square and rectangular shapes. A lateral pressure load, typical and important applied load condition to the plates of the hull structure for marine leisure boat, is simulated by employing a number of hydraulic cylinders operated automatically and manually. To examine and operate the structural test facility, five carbon/epoxy based FRP square plates having the test section area of $1m^2$, which are part of CFRP marine leisure boat hull, are prepared and they are subjected to monotonically increasing lateral pressure loads. In the test preparation, considering the symmetry of the plates geometry, various strain gauges and linear variable displacement transformer are used in conjunction with data acquisition system utilizing LabVIEW. From the test observation, the responses of the CFRP hull structure of marine leisure boat are understood by obtaining load to deflection and strain to load curves.

• 한국추진공학회지
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• 제23권1호
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• pp.46-51
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• 2019

Intermittent CSR 측정법을 이용하여 NBR 오링의 노화 거동과 수명 예측에 관하여 연구하였다. Intermittent CSR jig는 오링의 실제 사용 환경을 고려하여 설계 제작하였다. 오링의 노화 거동은 $40{\sim}120^{\circ}C$에서의 가속 노화 연구를 통하여 관찰하였다. 오링은 $80^{\circ}C$ 이하에서 비선형 노화 거동을 나타내었다. 오링의 수명은 고장 조건 20%에 대하여 Arrhenius plot으로부터 32.5년, WLF plot으로 부터 22.6년으로 나타났다.

• 한국기계가공학회지
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• 제21권3호
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• pp.56-62
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• 2022

The tank engine clutch flange constitutes a tank on which the engine and transmission of the tank are mounted. The engine clutch flange is fabricated using a difficult-to-cut material that exhibits high strength and hardness. It is difficult to process and requires considerable processing expertise. In addition, the engine clutch flange for the tank requires high machining precision because it is a system in which the connection is detachable. Because it requires high processing precision, the measurement of products equally important as processing. However, productivity is low owing to the significant amount of time required to measure each product using a three-dimensional coordinate measuring machine. Hence, this study is conducted to improve the productivity of the female tank engine clutch flange. Dedicated hobs and jigs are designed and manufactured to convert the existing end-mill cutting processing into hobbing cutting processing. An engine clutch for the tanks is manufactured using the manufactured dedicated hob and jig, and the shortening time is verified by measuring the processing time. In addition, a jig for inspection is designed and manufactured to measure the precision of the product. To verify the inspected product, the product precision is measured using a contact-type three-dimensional coordinate measuring machine and a surface roughness measuring instrument. The study confirmed that the productivity of the engine clutch flange product for tanks can be improved by simplifying the process, reducing the processing time, and simplifying product inspection.

• 한국정밀공학회지
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• 제10권2호
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• pp.114-125
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• 1993

In the present study the newly developed CAD/CAM system is applied to the process of the molding design, machining for mini-sized and precise processive die, and the production of press-stamped parts. When the design of a die was completed by means of CAD, wire cut NC data were generated with the aid of a design drawing in the CAD system and then inputed into the wire cut machine, and with the aid of a hole chart which had been made for this purpose, all the data were classified into the categories of CNC milling, jig boring, jig grinding, and machine center, and then developing a program of generating NC data, errors in process were reduced and programming time was shortened. The program was developed by using Autolisp language which was built-in the CAD, and realizing the intergation of designing a die, generating and processing NC data directly by a designer, designing time and machinery processing time were shorted. And the traditionally required working time for design. NC program required 6 days of work becomes 4 days of work by using the developed CAD/CAM system so that the efficiency shows 150% of the reduction working time. The prpgram of the design of the automation a progressive die mold was developed in the PC-Class Autocad system, therefore development expense could be reduced, and the integration of the CAD/CAM of the progressive die mold with the standard DB being built could be realized.

• 한국주조공학회지
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• 제14권6호
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• pp.520-529
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• 1994

This study describes the influence of the trace amount of sulphur on the nucleation behavior of graphite crystals in high purity Fe-C-Si alloys prepared by levitation melting method. Detailed microstructural analyses of high purity(HP) and sulphur added(HP＋S) samples showed that the nucleation of graphite crystals was prevented by sulphur. With decreasing the sulphur content, the shape of graphite crystals tended to spherulitic, and below 2ppm S, that of graphite crystals was only nodular. The critical cooling rate for the nucleation of griphite crystals was calculated as $1.5{\times}10^3k/s$. It is obvious from this work that residual C-C clusters act as an effective nucleation site for graphite crystals and one of the important role of nodularizing elements is to act as scavenger which removes harmful impurities from the solution.

• 한국주조공학회지
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• 제11권3호
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• pp.236-244
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• 1991

This paper describes a study of the nucleation and growth of graphite crystal of levitation melted high purity Fe-C-Si alloys with emphasis on hypereutectic composition. Spherulitic graphite was observed to form at high purity alloy and converted to compacted by changing the starting iron from ultra-pure zone refined iron to 99.95 pct electrolitic iron. Residual C-C clusters might be acting as an effective nucleation site for graphite, and sulphur was the element to prevent graphite from nucleating. The graphite morphology changed from compacted to spherulitic as the sulphur content decreased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1407-1409
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• 1995

This paper describes ozone concenteration($O_{3con}$), ozone generation($O_{3g}$) and ozone yield($O_{3Y}$) of lamp type ozonizer which be performed a role of lighting source and ozonizer. OLamp is consist of two of low pressure mercury lamps. The important conclusions obtained from this paper are as follows, The more quality of supplied gas(Q) decrease, the higher $O_{3con}$ rise. The more quality of supplied gas(Q) increase, the higher $O_{3g}$ some rise. When supplied oxygen 10[l/min] obtained 4,010[mg/kwh] $O_{3Y}$. The Echerichia coli which is reacted on ozone can be sterilized about 95[%].

• Journal of Interdisciplinary Genomics
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• 제2권2호
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• pp.20-25
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• 2020

Mucopolysaccharidosis type III (MPS III or Sanfilippo syndrome) is a multisystem lysosomal storage disease that is inherited in an autosomal recessive manner. It consists of four subtypes (MPS IIIA, B, C, and D), each characterized by the deficiency of different enzymes that catalyze the metabolism of the glycosaminoglycan heparan sulfate at the lysosomal level. The typical clinical manifestation of MPS III includes progressive central nervous system (CNS) degeneration with accompanying systemic manifestations. Disease onset is typically before the age of ten years and death usually occurs in the second or third decade due to neurological regression or respiratory tract infections. However, there is currently no treatment for CNS symptoms in patients with MPS III. Invasive and non-invasive techniques that allow drugs to pass through the blood brain barrier and reach the CNS are being tested and have proven effective. In addition, the application of genistein treatment as a substrate reduction therapy is in progress.