• 미생물학회지
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• 제44권2호
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• pp.135-139
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• 2008

2004년부터 207년까지 서울지역에서 산발적으로 발생한 급성위장관염 환자에 대하여 RT-PCR을 이용하여 노로바이러스를 검출하였다. 검출된 노로바이러스 258건에 대하여 염기서열분석을 실시한 결과 GII.1, GII.2, GII.3, GII.4, GII.5, GII.6, GII.8, GII.10, GII.12, GII.13, GII.15, GII.16, GII.17 등 13가지 유전자형이 검출되었으며 산발적으로 발생한 급성위장관염 환자에서 가장 많이 검출된 유전자형은 GII.4(76.7%)로 나타났다. 노로바이러스 유전자형의 다양성에 대한 연구로 서울지역 노로바이러스성 질환의 예방을 위한 기초자료로 활용될 것으로 기대된다.

• 한국통신학회논문지
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• 제41권10호
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• pp.1284-1289
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• 2016

최근, 디지털 영상처리는 방송, 통신, 컴퓨터 그래픽, 의학 분야 등에서 많이 응용되고 있으며, 일반적으로 영상 데이터는 전송하는 과정에서 잡음이 발생한다. 영상에 첨가되는 잡음에는 다양한 종류가 있으며, salt and pepper 잡음, AWGN, 복합잡음이 대표적이다. 따라서 본 논문에서는 영상에 첨가된 복합잡음의 영향을 완화하기 위하여 훼손된 영상을 네 개의 영역으로 세분화하고 각 화소들의 잡음 종류를 추정하여 salt and pepper 잡음과 AWGN으로 나누어 처리하는 스위칭 필터를 제안하였다. 국부 마스크의 중심화소가 salt and pepper 잡음에 훼손된 경우, 세분화된 영역의 히스토그램 확률 가중치 마스크를 이용하여 처리하였으며, AWGN으로 훼손된 경우, 세분화된 영역의 분산을 이용하여 각 영역의 분산에 따라 가중치를 다르게 적용하여 가중치 필터를 제안하였다. 그리고 제안한 필터의 성능 평가를 위해 PSNR을 이용하여 기존의 방법들과 비교하였다.

• 한국지능시스템학회논문지
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• 제26권6호
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• pp.485-492
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• 2016

이진화는 컴퓨터 비전 분야에서 전경과 배경을 분리하는 중요한 역할을 한다. 본 연구에서는 적응 퍼지 이진화 방법을 제안한다. 이동 창 내의 화소의 밝기 값 분포에 따라 ${\alpha}$-컷을 구하고, 이 값을 이용하여 이진화를 수행한다. ${\alpha}$-컷을 구하기 위해 수행속도가 빠른 기존의 이진화 방법들을 이용한다. 기존 방법들로 구해진 임계치들을 퍼지 소속 함수들의 중심값으로 설정하고, 화소의 밝기값 분포를 이용하여 퍼지 소속 함수들의 구간을 결정한다. 결정된 퍼지 소속 함수들을 이용하여 ${\alpha}$-컷의 조정율을 구하고, 각 화소의 소속도에 따라 이진화를 수행한다. 실험 결과는 제안한 방법이 기존의 방법들보다 전경과 배경이 효과적으로 분리될 수 있고, 전경의 손실이 적어지는 것을 보여준다.

• 한국산업융합학회 논문집
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• 제26권1호
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• pp.87-94
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• 2023

TMCP(Thermo Mechanical Control Process) steel was continuously cast (CC) by varying the argon gas flow rate and vacuum time in the Ruhrstahl Heraeus (RH) refining process. Using the CC specimens, the distribution of the inclusions and the mechanical properties were evaluated. A lot of oxides and Al-O type inclusions were observed. The average Vickers hardness did not show a constant, but showed dispersion in a certain range. The shape and scale parameters of the CC specimen with an argon gas flow rate of 160Nm³ and a vacuum time of 12 minutes was the best. Mechanical properties (tensile strength, yield strength and elongation) were consistent with the Weibull probability distribution analysis results. The impact resistance was the best for CC specimens with an argon flow rate of 140 Nm³ and a vacuum time of 12 minutes. Although the inclusions and mechanical properties of the CC specimens were evaluated according to the argon gas flow rate and vacuum time, these values were no significant difference.

• 공업화학
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• 제10권1호
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• pp.173-176
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• 1999

초임계수를 이용한 금속산화물의 미세입자 제조에 대하여 연구하였다. 금속염 수용액으로는 cobalt nitrate solution과 manganese nitrate solution을 sample solution으로 선택하여 코발트산화물과 망간산화물 입자를 제조하였다. 얻어진 결과로부터 초임계수를 이용한 금속산화물 미세입자의 제조가 가능함을 확인할 수 있었으며, 초임계수 하에서는 매우 빠른 dehydration반응이 일어남을 관찰할 수 있었다. 짧은 반응시간(30~100 초)에도 불구하고 미세입자 ($0.5{\sim}2{\mu}m$)가 생성되었으며, 초임계수 공정에서는 mixer의 온도가 입자의 크기 및 분포에 큰 영향을 미침을 알 수 있었다. 반응온도 조절을 통하여 입자의 크기를 제어할 수 있음을 확인할 수 있었다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제10권4호
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• pp.265-278
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• 2010

Module of the LED traffic signal is the core component for the care of driver and walker. Also it is important one to control the traffic. If it is against the criteria of brightness, it is the source of the people's death and traffic congestion. Therefore, it is a list of articles desired the security of stability. However, there is not the analysis of failure and not preserve the uniformity of quality. Therefore, it is necessary to establish the criteria of appreciation for the module of the LED traffic signal to analysis the data of failure. In this paper, we investigate the performance test, environment field test and test of reliability appreciation to improve the reliability. We also set up the criteria of success decision using the real measurement data.

• 한국생산제조학회지
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• 제20권1호
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• pp.34-39
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• 2011

Temperature control of a rubber injection mold is important for the dimensional accuracy of product. The main objective of this paper is to optimize the arrangement of heaters by FEM and optimal design method. Firstly, 3-dimensional transient heat transfer analysis was carried out for a square specimen mold. Results of FE analysis are a good agreement with the experimental results, showing about 1.22~7.22% error in temperature distribution. Secondly, we suggested the optimal method about an arrangement of heaters of rubber injection mold by using the optimal design technique. Distances between heater's center and the contact surface of mold, distances between heater's center and symmetric surface were considered as design variables. And the variances between the temperatures of cavity surfaces and their average temperature were used as the objective functions. Applying the optimal solution, the temperature variation was improved about 52.9~88.1 % compared to the existing mold. As a result of sensitivity analysis for design variables, design variables parallel to the direction of the split plane in mold affect the largest on the surface temperature variation in mold cavity.

• 한국정밀공학회지
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• 제30권2호
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• pp.143-147
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• 2013

We present results of the optical design and fabrication of a light-guiding plate (LGP) for a photobioreactor by using sunlight and a linear Fresnel lens. LGP patterns were designed by optical simulations with an illumination design tool, LightTools, and fabricated by using a computerized numerical control machine. Optical characteristics of average deviation of illuminance distribution and light throughput efficiency were measured and compared with simulation results.

• Tribology and Lubricants
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• 제18권5호
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• pp.357-363
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• 2002

The vibration characteristics of the pad fluttering in a fluid film tilting pad journal bearing (4-pad LBP) have been investigated experimentally under the different values of oil supply flow rate, bearing load and shaft speed. The vibration characteristics of the pad fluttering are estimated by measuring the time signal of circumferential distribution of the film thickness and the cascade plot of the response of the relative displacement between the bearing and the shaft. It is shown that the vibration frequency of the pad fluttering has a sub-synchronous frequency and almost does not change by the increase of shaft speed. However the vibration amplitude is increased by the increase of shaft speed. From those experimental results, pad fluttering can be thought of as a self-excited vibration. The incipient pad fluttering velocity is increased by the increase of oil supply flow rate and by the decrease of bearing load. It is observed that the vibration amplitude of the pad fluttering can be decrease by the control of supply oil flow rate effectively. And also It is known that the outbreak of pad fluttering does not concern with the shaft vibration.

• 센서학회지
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• 제21권2호
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• pp.103-108
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• 2012

Radiofrequency(RF) signal is a key medium to the most of the present wireless communication devices including RF identification devices(RFID) and smart sensors. However, the most critical barrier to overcome in RFID application is in the failure rate in detection. The most notable improvement in the detection was from the introduction of EPC Class1 Gen2 protocol, but the fundamental problems in the physical properties of the RF signal drew less attention. In this work, we focused on the physical properties of the RF signal in order to understand the failure rate by noting the existence of the ground planes and noise sources in the real environment. By using the mathematical computation software, Maple, we simulated the distribution of the electromagnetic field from a dipole antenna when ground planes exist. Calculations showed that the dark area can be formed by interference. We also constructed a test system to measure the failure rate in the detection of a RFID transponder. The test system was composed of a fixed RFID reader and an EPC Class1 Gen2 transponder which was attached to a scanner to sweep in the x-y plane. Labview software was used to control the x-y scanner and to acquire data. Tests in the laboratory environment showed that the dark area can be as much as 43 %. One who wants to use RFID and smart sensors should carefully consider the extent of the dark area.